Posts tagged Computer Networking
The Benefits Of Soundproof Enclosures In The Office Work Space
Mar 16th
If you have had to work next to the hum of a server you’ll appreciate the calming influence a soundproof enclosure can bring. Even the simplest tasks become difficult when loud equipment disturbs your working environment.
Owning my own business has presented me with many hurdles to overcome but nothing is more frustrating than constantly trying to motivate distracted staff, so when presented with this problem, I spoke to fellow business owners who recommended UCoustic Soundproof enclosures which they assured me would provide a practical solution to my dilemma.
Having never heard of Soundproof enclosures, I do not know too much about the technology behind them and I can’t give you a break down of how it works but take it from me, they do! In the beginning I was hesitant, and doubted that it would have much of an effect, but the drastic reduction in noise levels was incredible from the minute it was installed. Working in a professional streamlined office, I can vouch for its sleek contemporary design and the results are plain to see; the UCoustic cab boasts a reduction of 28.5dBA so within an office environment it is virtually silent.
The benefits of the UCoustic soundproof enclosure are:
Noticeable reduction in office noise levels, drastic increase in staff productivity, Stylish streamlined construction, Cutting edge technology, Far cheaper than office re-modeling,
I couldn’t be more impressed with my UCoustic cabinet and my staff all tell me they find it much easier to concentrate without the distracting noise the old server made. From a financial point of view, it is a tiny fraction of what it would have cost me to build a dedicated server cupboard and the reliability and excellent build quality mean that maintenance costs are kept to a minimum! I wouldn’t be able to go back to a regular office without a UCoustic Enclosure and I would not want my business or my staff to suffer as a result. All in all, the UCoustic soundproof enclosure has helped to increase the office space, as well as improve the working environment and the morale of the staff and my office would not be without one!
If you would like to find out more about Soundproof Enclosures then visit USystems Ltd, to find out more about the UCoustic Soundproof Enclosure and how it can improve your working environment. Don’t reprint this exact article. Instead, reprint a free unique content version of this same article.
There Be A Monster In That There Lake!
Mar 15th
Ronky The Monster Of Lake Ronkonkoma New York
It was a Sunday in Summer of 2009 went I first saw Ronky with my own eyes. I had heard stories of Ronky here and there, They had come to me in Whispers really.The History of Ronky has been a well kept secret for Hundreds maybe Thousands of years. I had spent weeks watching this lake in Lake Ronkonkoma on Long Island in New York State. This day I was driving around going past one of the many Parks and Beaches around the lake. While I was going North on Lake Shore Road I saw something in the water out of the corner of my eye, but after weeks of watching this lake I thought it was just someone out on another blow up raft and didn’t really think much of it !
As I was passing the Dinning Hall “Windows on the Lake” there is an opening where Guests can get a good look at the lake. I looked over and I saw what I had though to be a raft a few seconds before was the creature. I though to myself this could just be another hoax! After years of searches and hunts leading to nothing but dead ends I was not going to get my hopes up to fast. I slowed down and watched as the Creature swam around the lake enjoying itself! I was a little scared but at the same time I could not stop myself from smiling thinking this was really it!
I drove around the lake following along with “Ronky” at some point I pulled into a parking lot and walked onto one of the beaches. I slowly got my Camera out fearing as soon as I went to take the picture the creature would disappear. I snapped a shot, checked it in the review mode of the Camera and I could not believe I had captured a perfect shot of the Creature that no one could dispute the authenticity of ! When I looked back at the Lake Ronky was gone.
Over the next few days I carefully started asking the locals in the area if they had ever seen something weird in the Lake? It seems that to everyone in Lake Ronkonkoma Ronky is well known. He is not a myth or urban legend here. He is just another Member of the Village! I have been told there are two Differences between Nessie in Scotland’s Loch ness and Ronky in New York’s Lake Ronkonkoma. One Ronky is real and Two Ronky is protected by the Locals and his name is not defiled for tourist money.
There are many stories of Ronky that go back Hundreds of years. The one I found most interesting was a story that happened about 15 years ago. It seems there was an expedition sent to look into and map the depths and some underwater streams under Lake Ronkonkoma. This expedition never happened. The Official Story given was the expedition ran out of Money and was going to come back when they got more funds. I was told by an old time resident that wishes her Identity to remain a secret that the real story is a group called the “Keepers of the Lake” told the expiation in no uncertain terms it would be in their best interested for them to leave and not come back!!!
The people of Lake Ronkonkoma have kept this Monster Ronky loved and Protected for many years! I respect and sympathize with them,but I have spent my adult life and most of my families fortune searching for a creature like Ronky.This is my job and I must share this with the world. I have received many threats not to print this story! I have posted it here to go out to these newsgroups if I do not reset the settings at least once a week. If you are reading this there is a good chance something has happen to me. Please do not let what I have spent my life hunting for go unheard of ! Ronky is there in that Lake!
By Lawrence Jamison http://www.lakeronkonkomacivic.org
Larry J has been seeking out Lake Monsters for years . Larry J love the fact that the folks of Ronkonkoma have hidden Ronky rather then use him for Tourism Get a totally unique version of this article from our article submission service
CWNA Certification – Certified Wireless Network Administrator
Mar 12th
A CWNA expert has the technical leadership and the ability to successfully put into operation any wireless solution and offers a career demarcation, with enhanced trustworthiness and marketability. A CWNA certification is the initial step towards a successful career in the wireless field. Because it is vendor-neutral, you have the advantage of being employed by any company or organization having any wireless infrastructure vendor
CWNA Exam Requirement To earn the CWNA certification you must pass the CWNA PW0-104 exam. This is a multiple-choice exam with 60 questions, for 90 minutes exam duration. You need a passing score of 70%. You can register at any time for the course.
With wireless technology, people have more flexibility and more freedom to connect with their favorite content and to communicate with others even when they are on the move”.. All sorts of devices support now the wireless technology Wireless technology has a quickly growing marketability. Wi-Fi technology has brought “Freedom and flexibility in Communication.
CWNA Course and Preparation The combination of the two study resources above will definitely help you to pass the exam guaranteed. Especially the Train signal Video Training package will provide you with an “instructor-like” experience which covers all required topics for the exam For optimal CWNA preparation I suggest to get the only authorized CWNA Video Training (from Train signal) together with the Official CWNA Self-Study Guide (709 pages paperback) from the official website (cwnp.com).
CWNA Exam Requirement To earn the CWNA certification you must pass the CWNA PW0-104 exam. This is a multiple-choice exam with 60 questions, for 90 minutes exam duration. You need a passing score of 70%. You can register at any time for the course.
The certification exam measures your ability to administer any wireless LAN. The exam covers a broad range of wireless LAN topics focused on 802.11 wireless technology rather than products of specific vendors. The main topics covered by the exam are the following:Radio Technologies; Antenna Concepts; Wireless LAN 0Hardware and Software;Network Design, Installation, and Management;Wireless Standards and Organizations;802.11 Network Architecture:Wireless LAN Security ;Troubleshooting and How to Perform Site Surveys
Want to find out more about online training, then visit Sharief Patel’s site on how to choose the best online courses for your needs. Get a totally unique version of this article from our article submission service
Home Business Necessities
Mar 12th
Every home and business office nowadays finds it very important to have desktop computers. Even the smallest companies cannot do its ordinary processes without the use of these digital wonders. Homes, on the other hand, have found it necessary in aiding the kids’ homework and research and in providing cheap and real-time communication.
Another electronic device that is gaining the same amount of importance is the server. In the era of the internet when connectivity among people has a paramount advantage, servers have become just as valuable as PCs. Aside from allowing access to a network of computers, it provides common storage for users, facilitating file sharing in the most convenient manner.
However, to get the most advantages in one’s computing jobs, having both is the most ideal. Having only a desktop PC means being limited in terms of accessibility. Most of these run only to several hundreds of gigabytes in storage space. This is definitely not enough for the heavy user; more so for network use.
A server, on the other hand is useless, without a PC interface. It merely stores files, which can be accessible anytime for all users linked to it. It has to be left on 24 hours so that it its public files are always available and so that it constantly connects computers in a network.
The combination of both servers and desktop computers provide the user with the best advantage. In fact, the internet has become possible with the connection of both pieces of equipment. The server is the means for common storage and for making access possible while the desktop PC is the tool for manipulating it and for opening the files.
These equipments do have varying limitations when set apart and used separately. These limitations are avoided when connected and used together. Through your PC, you can access a file saved in a network’s server or you may play a network game with other users online. The server makes all PC network connections possible.
It is more likely that you already have a PC. It is easy for you to get a server. With the minimum of $300, you already buy one of the simpler servers in the market. If you find this pricey still, you can just ask someone who converts desktop computers to it.
He may also prefer to avail of online servers instead. He can do this by paying for memberships in such websites who accommodate people’s files for storage. He has to pay a monthly rate. He can access these files from all desktop computers connected to the internet. However, there are limits to the amount stored. Therefore, it is still recommended to have server hardware of his own.
As a business it is always better to have a Server ready for file sharing purposes. However, some other business may be just fine with a Desktop Computer (computadora) with certain network benefits in place.
Positive Ways To Using High Tech For Laptop Repair
Mar 11th
Computers have been around for many years. In fact, the concept of computer hardware existed as far back as World War II. Laptops actually did not exist until the 1980s. Laptops today are faster and more sophisticate, which need special attention when repairing. Unfortunately laptops wear out, whether parts break or the whole model needs replacing. With proper care, and repair, laptops can exist beyond their normal time. Using high tech for laptop repair makes upkeep a lot easier.
Laptops are built with many interchangeable parts. This is a compliment of companies who mass- produce parts. However, it is not easy to replace or repair specific pieces like the processor, motherboard, and hard drive. These few parts usually need a full replacement and cannot be repaired.
Technicians are rigorously trained in school to know what each piece does, and how to troubleshoot any problems that may arise. Sometimes these technicians also offer services like removing stubborn Trojan viruses that have shut the user out of the system. However, normal people who have taken the time to study computers and laptops may also be able to conduct normal repairs. This is usually due to the fact that most systems have been designed as “plug and play”. This means that the user only needs to install the part and the computer automatically recognizes it in the system.
Laptops are a more compact version of full desktop computers. They contain many parts, especially ones that are smaller and more difficult to fix. Working with such contraptions involves taking other pieces out just to get to the part that is the problem. Some of the thinnest laptops are not even an inch thick. Just imagine how small the parts are!
Some of the more advanced tools to laptop repair are temperature gauges and a multi- meter. The temperature monitor allows the technician to know if a coolant fan or any of the other parts are overheated. The multi- meter is a tool that checks relays in the laptop to see if the power is flowing properly. The technique to repairing often involves a lot of experimenting and applying solutions until the computer is fixed. The ability to be patient and also creative enough to look at the problem in a unique way is really important.
Some of the other tools used in fixing laptops are simple and look like normal house tools, but they are just as important. They are designed to handle small and delicate pieces. Handling laptop repair is not a job that requires muscle. Too much pressure or being rough will crush or break important parts that could prove costly.
One of the most common problems with laptops is a burnt out fan. Fixing such an issue involves replacing the fan itself. The computer repair technician has to open the laptop, pull out a few other parts before reaching the fan itself. To remove the fan, the technician needs to disconnect a few cables. Although this sounds simple, it is not and should be done with deft hands.
A lot of companies offer warranties to customers to repair parts as they already carry the necessary pieces. A lot of times they just replace, rather than repair. However, technicians who run small businesses in this niche take the time to check each part with their monitors and explain to the customer what is going on with their laptop. They also explain what solutions they recommend.
The technology today is a big help for those in the computer repair business. The monitors and small tools to assist in troubleshooting make jobs easier. Another great help is the manuals published through the years for technicians. Now, there are even tutorials on the Internet for laptop repair too!
Canadian home-computer company provides technical solutions such as: Laptop repair Montreal, onsite Computer repair Ottawa service in Toronto, Hamilton, Niagara. We also offer computer virus removal.
Making Network Administration Easy Through Network Management and Administration Software
Mar 7th
The innovations in computer technology provide a big help in big networks. A network is usually composed of numerous units which have specific duties and services to offer by relying on the tools at their command. Performing their tasks manually can impossibly let them achieve the daily goals of the network. Fortunately, there are innovative software that can address concerns about network administration.
Administrating a particular network can be physically taxing. This task can be more laborious if the network administrator will do the entire surveillance manually. Aside from being physically taxing, this job can take out a lot of time which means loss of client which means loss of income. Hence, the use of network management software or network administration software is highly necessary.
Network management and network administration software is widely used in all network companies to aid the operation, management, administration of networked systems. The person who takes charged of the department that deals with network administration is called network administrator for he administers the maintenance and operation of computer hardware and software.
Searching out for network management software can be easy. In fact, there are a number of companies that sell this software in the market competitively. But, looking for the best can be difficult since best features are not available in all network management software. The most searched out features include the capability of the software to provide integrated administration in the entire network, provide great support for configuration, accounting, performance, and security, provide interface that can make all elements of network visible, determine problems and areas of services affected by problems, and mix all network layers’ views.
There are top calibre network management software in the market today. Ground Monitor is included in the list because of its features that include new web front end, commercial support, and active development integration. Installation problems are the only drawback of this software. It can be bought in the market for an amount that ranges from 8 to 16 thousand. Nagios is also included in the list of best software in the market. Its best features include its capability to monitor network services, host resources, and environmental factors like temperature. Installing Nagios can take much time since it is done manually.
Included in the list of top calibre network management software titles are Centreon, OpenNMS, ZABBIX, and NINO. Centreon specializes on supervising and monitoring applications and its capability to provide new front end and functionalities to Nagios comprise its best feature. OpenNMS is a tool that can provide three general services on service polling, performance, and event administration and notification. ZABBIX is an alternative to Centreon because it can monitor servers and network. NINO is a tool for managing routers, servers, switches, and applications.
The foregoing software are just few of the network administration software available. If you have hard time looking out for this type of software, then avail of the web. The web provides many sites where you can download many software at different costs or no costs at all. However, read first the honest user reviews before you decide to buy.
If you want better network administration, then avail now of network management or network administration software.
Because man hours are just not enough. Network management software and network administration software are provided to increase network functionality that you can’t get with more employees. Look what network software can do for you.
CCNA Knowledge: Access Control Lists
Mar 5th
In preparation of our CCNA exam, we want to make sure we cover the various concepts that we could see on our Cisco CCNA exam. So to assist you, below we will discuss Access Control Lists.
You can configure network security by using ACLs by either using the Cluster Management Suite (CMS) or through the command-line interface (CLI).
You can also use the security wizard to filter inbound traffic on the Catalyst 2950 switches. Filtering can be based on network addresses or TCP/UDP applications. You can choose whether to drop or forward packets that meet the filtering criteria. To use this wizard, you must know how the network is designed and how interfaces are used on the filtering device.
Understanding ACLs
Packet filtering can limit network traffic and restrict network use by certain users or devices. ACLs can filter traffic as it passes through a switch and permit or deny packets from crossing specified interfaces. An ACL is a sequential collection of permit and deny conditions that apply to packets. When a packet is received on an interface, the switch compares the fields in the packet against any applied ACLs to verify that the packet has the required permissions to be forwarded, based on the criteria specified in the access lists. The switch tests the packet against the conditions in an access list one by one. The first match determines whether the switch accepts or rejects the packet. Because the switch stops testing conditions after the first match, the order of conditions in the list is critical. If no conditions match, the switch rejects the packet. If there are no restrictions, the switch forwards the packet; otherwise, the switch drops the packet.
You configure access lists on a Layer 2 switch to provide basic security for your network. If you do not configure ACLs, all packets passing through the switch could be allowed onto all parts of the network. You can use ACLs to control which hosts can access different parts of a network or to decide which types of traffic are forwarded or blocked at switch interfaces. For example, you can allow e-mail traffic to be forwarded but not Telnet traffic. ACLs can be configured to block inbound traffic.
An ACL contains an ordered list of access control entries (ACEs). Each ACE specifies permit or deny and a set of conditions the packet must satisfy in order to match the ACE. The meaning of permit or deny depends on the context in which the ACL is used.
The switch supports these types of ACLs:
IP ACLs filter IP traffic, including TCP and User Datagram Protocol (UDP). Ethernet ACLs filter Layer 2 traffic. ACLs
You can apply ACLs on management VLANs, and on physical Layer 2 interfaces. ACLs are applied on interfaces for inbound directions.
Standard IP access lists use source addresses for matching operations. Extended IP access lists use source and destination addresses and optional protocol type information for matching operations. MAC extended access list use source and destination mac addresses and optional protocol type information for matching operations. The switch examines access lists associated with features configured on a given interface and a direction. As packets enter the switch on an interface, ACLs associated with all inbound features configured on that interface are examined.
ACLs permit or deny packet forwarding based on how the packet matches the entries in the ACL. For example, you can use ACLs to allow one host to access a part of a network, but to prevent another host from accessing the same part. In Figure 12-1, ACLs applied at the switch input allow Host A to access the Human Resources network, but prevent Host B from accessing the same network.
Figure 12-1 Using ACLs to Control Traffic to a Network
Handling Fragmented and Unfragmented Traffic
IP packets can be fragmented as they cross the network. When this happens, only the fragment containing the beginning of the packet contains the Layer 4 information, such as TCP or UDP port numbers, ICMP type and code, and so on. All other fragments are missing this information. Some ACEs do not check Layer 4 information and therefore can be applied to all packet fragments. ACEs that do test Layer 4 information cannot be applied in the standard manner to most of the fragments in a fragmented IP packet. When the fragment contains no Layer 4 information and the ACE tests some Layer 4 information, the matching rules are modified:
Permit ACEs that check the Layer 3 information in the fragment (including protocol type, such as TCP, UDP, and so on) are considered to match the fragment regardless of what the missing Layer 4 information might have been. Deny ACEs that check Layer 4 information never match a fragment unless the fragment contains Layer 4 information. Consider access list 102, configured with these commands, applied to three fragmented packets:
Switch (config)# access-list 102 permit tcp any host 10.1.1.1 eq smtp Switch (config)# access-list 102 deny tcp any host 10.1.1.2 eq telnet Switch (config)# access-list 102 deny tcp any any
Note In the first and second ACEs in the examples, the eq keyword after the destination address means to test for the TCP-destination-port well-known numbers equaling Simple Mail Transfer Protocol (SMTP) and Telnet, respectively.
Packet A is a TCP packet from host 10.2.2.2, port 65000, going to host 10.1.1.1 on the SMTP port. If this packet is fragmented, the first fragment matches the first ACE (a permit), as if it were a complete packet because all Layer 4 information is present. The remaining fragments also match the first ACE, even though they do not contain the SMTP port information because the first ACE only checks Layer 3 information when applied to fragments. (The information in this example is that the packet is TCP and that the destination is 10.1.1.1.) Packet B is from host 10.2.2.2, port 65001, going to host 10.1.1.2 on the Telnet port. If this packet is fragmented, the first fragment matches the second ACE (a deny) because all Layer 3 and Layer 4 information is present. The remaining fragments in the packet do not match the second ACE because they are missing Layer 4 information. Because the first fragment was denied, host 10.1.1.2 cannot reassemble a complete packet, so packet B is effectively denied. However, the later fragments that are permitted will consume bandwidth on the network and resources of host 10.1.1.2 as it tries to reassemble the packet. Fragmented packet C is from host 10.2.2.2, port 65001, going to host 10.1.1.3, port ftp. If this packet is fragmented, the first fragment matches the third ACE (a deny). All other fragments also match the third ACE because that ACE does not check any Layer 4 information and because Layer 3 information in all fragments shows that they are being sent to host 10.1.1.3, and the earlier permit ACEs were checking different hosts. Understanding Access Control Parameters
Before configuring ACLs on the Catalyst 2950 switches, you must have a thorough understanding of the Access Control Parameters (ACPs). ACPs are referred to as masks in the switch CLI commands, output, and CMS. Each ACE has a mask and a rule. The Classification Field or mask is the field of interest on which you want to perform an action. The specific values associated with a given mask are called rules. Packets can be classified on these Layer 2, Layer 3, and Layer 4 fields.
Layer 2 fields: o Source MAC address (Specify all 48 bits.) o Destination MAC address (Specify all 48 bits.) o Ethertype (16-bit ethertype field)
You can use any combination or all of these fields simultaneously to define a flow.
Layer 3 fields: o IP source address (Specify all 32 IP source address bits to define the flow, or specify an user- defined subnet. There are no restrictions on the IP subnet to be specified.) o IP destination address (Specify all 32 IP destination address bits to define the flow, or specify an user- defined subnet. There are no restrictions on the IP subnet to be specified.)
You can use any combination or all of these fields simultaneously to define a flow.
Layer 4 fields: o TCP (You can specify a TCP source, destination port number, or both at the same time.) o UDP (You can specify a UDP source, destination port number, or both at the same time.)
Note A mask can be a combination of either multiple Layer 3 and Layer 4 fields or of multiple Layer 2 fields. Layer 2 fields cannot be combined with Layer 3 or Layer 4 fields.
There are two types of masks:
User-defined mask-masks that are defined by the user. System-defined mask-these masks can be configured on any interface: Switch (config-ext-nacl)# permit tcp any any Switch (config-ext-nacl)# deny tcp any any Switch (config-ext-nacl)# permit udp any any Switch (config-ext-nacl)# deny udp any any Switch (config-ext-nacl)# permit ip any any Switch (config-ext-nacl)# deny ip any any Switch (config-ext-nacl)# deny any any Switch (config-ext-nacl)# permit any any
Note In an IP extended ACL (both named and numbered), a Layer 4 system-defined mask cannot precede a Layer 3 user-defined mask. For example, a Layer 4 systemdefined mask such as permit tcp any any or deny udp any any cannot precede a Layer 3 user-defined mask such as permit ip 10.1.1.1 any. If you configure this combination, the ACL is not configured. All other combinations of system-defined and user-defined masks are allowed in security ACLs.
The Catalyst 2950 switch ACL configuration is consistent with other Cisco Catalyst switches. However, there are significant restrictions as well as differences for ACL configurations on the Catalyst 2950 switches.
Guidelines for Configuring ACLs on the Catalyst 2950 Switches
These configuration guidelines apply to ACL filters:
Only one ACL can be attached to an interface. For more information, refer to the ip access-group interface command in the Catalyst 2950 Desktop Switch Command Reference. All ACEs in an ACL must have the same user-defined mask. However, ACEs can have different rules that use the same mask. On a given interface, only one type of user-defined mask is allowed, but you can apply any number of system-defined masks. This example shows the same mask in an ACL: Switch (config)#ip access-list extended acl2 Switch (config-ext-nacl)# permit tcp 10.1.1.1 0.0.0.0 any eq 80 Switch (config-ext-nacl)# permit tcp 20.1.1.1 0.0.0.0 any eq 23
In this example, the first ACE permits all the TCP packets coming from the host 10.1.1.1 with a destination TCP port number of 80. The second ACE permits all TCP packets coming from the host 20.1.1.1 with a destination TCP port number of 23. Both the ACEs use the same mask; therefore, a Catalyst 2950 switch supports this ACL.
Only four user-defined masks can be defined for the entire system. These can be used for either security or quality of service (QoS) but cannot be shared by QoS and security. You can configure as many ACLs as you require. However, a system error message appears if ACLs with more than four different masks are applied to interfaces. Table 12-1 lists a summary of the ACL restrictions on Catalyst 2950 switches.
Table 12-1 Summary of ACL Restrictions
Configuring ACLs
Configuring ACLs on Layer 2 or Layer 3 management VLAN interfaces is the same as configuring ACLs on Cisco routers. The process is briefly described here.
Unsupported Features
The Catalyst 2950 switch does not support these IOS router ACL-related features:
Non-IP protocol ACLs (see Table 12-2). Bridge-group ACLs. IP accounting. No ACL support on the outbound direction. Inbound and outbound rate limiting (except with QoS ACLs). IP packets with a header length of less than five are not be access-controlled. Reflexive ACLs. Dynamic ACLs (except for certain specialized dynamic ACLs used by the switch clustering feature. ICMP-based filtering. IGMP-based filtering. Creating Standard and Extended IP ACLs
This section describes how to create switch IP ACLs. An ACL is a sequential collection of permit and deny conditions. The switch tests packets against the conditions in an access list one by one. The first match determines whether the switch accepts or rejects the packet. Because the switch stops testing conditions after the first match, the order of the conditions is critical. If no conditions match, the switch denies the packet.
Use these steps to use ACLs:
Step 1 Create an ACL by specifying an access list number or name and access conditions.
Step 2 Apply the ACL to interfaces or terminal lines.
The software supports these styles of ACLs or IP access lists:
Standard IP access lists use source addresses for matching operations. Extended IP access lists use source and destination addresses for matching operations and optional protocol-type information for finer granularity of control. MAC extended access list use source and destination MAC addresses and optional protocol type information for matching operations. The next sections describe access lists and the steps for using them.
ACL Numbers
The number you use to denote your ACL shows the type of access list that you are creating. Table 12-2 lists the access list number and corresponding type and shows whether or not they are supported by the switch. The Catalyst 2950 switch supports IP standard and IP extended access lists, numbers 1 to 199 and 1300 to 2699.
Table 12-2 Access List Numbers
Note In addition to numbered standard and extended ACLs, you can also create standard and extended named IP ACLs by using the supported numbers. That is, the name of a standard IP ACL can be 1 to 99; the name of an extended IP ACL can be 100 to 199. The advantage of using named ACLs instead of numbered lists is that you can delete individual entries from a named list.
Creating a Numbered Standard ACL
Beginning in privileged EXEC mode, follow these steps to create a numbered standard ACL:
Use the no access-list access-list-number global configuration command to delete the entire ACL. You cannot delete individual ACEs from numbered access lists.
Note When creating an ACL, remember that, by default, the end of the ACL contains an implicit deny statement for all packets that it did not find a match for before reaching the end. With standard access lists, if you omit the ask from an associated IP host address ACL specification, 0.0.0.0 is assumed to be the mask.
This example shows how to create a standard ACL to deny access to IP host 171.69.198.102, permit access to any others, and display the results.
Switch (config)# access-list 2 deny host 171.69.198.102 Switch (config)# access-list 2 permit any Switch(config)# end Switch# show access-lists Standard IP access list 2 deny 171.69.198.102 permit any
Creating a Numbered Extended ACL
Although standard ACLs use only source addresses for matching, you can use an extended ACL source and destination addresses for matching operations and optional protocol type information for finer granularity of control. Some protocols also have specific parameters and keywords that apply to that protocol.
These IP protocols are supported (protocol keywords are in parentheses in bold): Internet Protocol (ip), Transmission Control Protocol (tcp), or User Datagram Protocol (udp).
Supported parameters can be grouped into these categories:
TCP UDP Table 12-3 lists the possible filtering parameters for ACEs for each protocol type.
Table 12-3 Filtering Parameter ACEs Supported by Different IP Protocols
For more details on the specific keywords relative to each protocol, refer to the Cisco IP and IP Routing Command Reference for IOS Release 12.1.
Note The Catalyst 2950 switch does not support dynamic or reflexive access lists. It also does not support filtering based on the minimize-monetary-cost type of service (TOS) bit.
When creating ACEs in numbered extended access lists, remember that after you create the list, any additions are placed at the end of the list. You cannot reorder the list or selectively add or remove ACEs from a numbered list.
Beginning in privileged EXEC mode, follow these steps to create an extended ACL:
Use the no access-list access-list-number global configuration command to delete the entire access list. You cannot delete individual ACEs from numbered access lists.
This example shows how to create and display an extended access list to deny Telnet access from any host in network 171.69.198.0 to any host in network 172.20.52.0 and permit any others. (The eq keyword after the destination address means to test for the TCP destination port number equaling Telnet.)
Switch(config)# accesslist 102 deny tcp 171.69.198.0 0.0.0.255 172.20.52.0 0.0.0.255 eq telnet Switch(config)# access-list 102 permit tcp any any Switch(config)# end Switch# show access-lists Extended IP access list 102 deny tcp 171.69.198.0 0.0.0.255 172.20.52.0 0.0.0.255 eq telnet permit tcp any any
After an ACL is created, any additions (possibly entered from the terminal) are placed at the end of the list. You can add ACEs to an ACL, but deleting any ACE deletes the entire ACL.
Note When creating an ACL, remember that, by default, the end of the access list contains an implicit deny statement for all packets if it did not find a match before reaching the end.
After creating an ACL, you must apply it to a line or interface.
Creating Named Standard and Extended ACLs
You can identify IP ACLs with an alphanumeric string (a name) rather than a number. You can use named ACLs to configure more IP access lists on a switch than if you use numbered access lists. If you identify your access list with a name rather than a number, the mode and command syntax are slightly different. However, not all commands that use IP access lists accept a named ACL.
Note The name you give to a standard ACL or extended ACL can also be a number in the supported range of access list numbers. That is, the name of a standard IP ACL can be 1 to 99; the name of an extended IP ACL can be 100 to 199. The advantage of using named ACLs instead of numbered lists is that you can delete individual entries from a named list.
Consider these guidelines and limitations before configuring named ACLs:
A standard ACL and an extended ACL cannot have the same name. Numbered ACLs are also available, as described in the “Creating Standard and Extended IP ACLs” section. Beginning in privileged EXEC mode, follow these steps to create a standard access list using names:
Beginning in privileged EXEC mode, follow these steps to create an extended ACL using names:
When making the standard and extended ACL, remember that, by default, the end of the ACL contains an implicit deny statement for everything if it did not find a match before reaching the end. For standard ACLs, if you omit the mask from an associated IP host address access list specification, 0.0.0.0 is assumed to be the mask.
After you create an ACL, any additions are placed at the end of the list. You cannot selectively add ACEs to a specific ACL. However, you can use no permit and no deny commands to remove ACEs from a named ACL. This example shows how you can delete individual ACEs from a named ACL:
Switch(config)# ip access-list extended border-list Switch(config-ext-nacl)# no permit ip host 10.1.1.3 any
Being able to selectively remove lines from a named ACL is one reason you might use named ACLs instead of numbered ACLs.
After creating an ACL, you must apply it to a line or interface.
Including Comments About Entries in ACLs
You can use the remark command to include comments (remarks) about entries in any IP standard or extended ACL. The remarks make the ACL easier for you to understand and scan. Each remark line is limited to 100 characters.
The remark can go before or after a permit or deny statement. You should be consistent about where you put the remark so that it is clear which remark describes which permit or deny statement. For example, it would be confusing to have some remarks before the associated permit or deny statements and some remarks after the associated statements. For IP numbered standard or extended ACLs, use the access-list access-list number remark remark global configuration command to include a comment about an access list. To remove the remark, use the no form of this command.
In this example, the workstation belonging to Jones is allowed access, and the workstation belonging to Smith is not allowed access:
Switch(config)# access-list 1 remark Permit only Jones workstation through Switch(config)# access-list 1 permit 171.69.2.88 Switch(config)# access-list 1 remark Do not allow Smith workstation through Switch(config)# access-list 1 deny 171.69.3.13
For an entry in a named IP ACL, use the remark access-list global configuration command. To remove the remark, use the no form of this command.
In this example, the Jones subnet is not allowed to use outbound Telnet:
Switch(config)# ip access-list extended telnetting Switch(config-ext-nacl)# remark Do not allow Jones subnet to telnet out Switch(config-ext-nacl)# deny tcp host 171.69.2.88 any eq telnet
Applying the ACL to an Interface or Terminal Line
After you create an ACL, you can apply it to one or more interfaces or terminal lines. ACLs can be applied on inbound interfaces. This section describes how to accomplish this task for both terminal lines and network interfaces. Note these guidelines:
When controlling access to a line, you must use a number. Numbered ACLs and MAC extended ACLs can be applied to lines. When controlling access to an interface, you can use a name or number. Set identical restrictions on all the virtual terminal lines because a user can attempt to connect to any of them. If you apply an ACL to a Layer-3 interface, the ACL only filters packets that are intended for the CPU, such as SNMP, Telnet or Web traffic. Beginning in privileged EXEC mode, follow these steps to restrict incoming connections between a virtual terminal line and the addresses in an ACL:
Beginning in privileged EXEC mode, follow these steps to control access to a Layer 2 or Layer 3 interface:
This example shows how to apply access list 2 on Gigabit Ethernet interface 0/3 to filter packets entering the interface:
Switch(config)# interface gigabitethernet0/3 Router(config-if)# ip access-group 2 in
Note The ip access-group interface configuration command is only valid when applied to an management interface, a Layer 2 interface, or a Layer 3 interface. If applied to a Layer 3 interface, the interface must have been configured with an IP address. ACLs cannot be applied to interface port-channels.
For inbound ACLs, after receiving a packet, the switch checks the packet against the ACL. If the ACL permits the packet, the switch continues to process the packet. If the ACL rejects the packet, the switch discards the packet.
When you apply an undefined ACL to an interface, the switch acts as if the ACL has not been applied to the interface and permits all packets. Remember this behavior if you use undefined ACLs for network security.
Displaying ACLs
You can display existing ACLs by using show commands.
Beginning in privileged EXEC mode, follow these steps to display access lists:
This example displays all standard and extended ACLs:
Switch# show access-lists Standard IP access list 1 permit 172.20.10.10 Standard IP ACL 10 permit 12.12.12.12 Standard IP access list 12 deny 1.3.3.2 Standard IP access list 32 permit 172.20.20.20 Standard IP access list 34 permit 10.24.35.56 permit 23.45.56.34 Extended IP access list 120 Extended MAC access list mac1
This example displays only IP standard and extended ACLs.
Switch# show ip access-lists Standard IP access list 1 permit 172.20.10.10 Standard IP access list 10 permit 12.12.12.12 Standard IP access list 12 deny 1.3.3.2 Standard IP access list 32 permit 172.20.20.20 Standard IP access list 34 permit 10.24.35.56 permit 23.45.56.34 Extended IP access list 120
Displaying Access Groups
You use the ip access-group interface configuration command to apply ACLs to a Layer 3 interface. When IP is enabled on an interface, you can use the show ip interface interface-id privileged EXEC command to view the input and output access lists on the interface, as well as other interface characteristics. If IP is not enabled on the interface, the access lists are not shown.
This example shows how to view all access groups configured for VLAN 1 and for Gigabit Ethernet interface 0/2:
Switch# show ip interface vlan 1 GigabitEthernet0/2 is up, line protocol is down Internet address is 10.20.30.1/16 Broadcast address is 255.255.255.255 Address determined by setup command MTU is 1500 bytes Helper address is not set Directed broadcast forwarding is disabled Outgoing access list is permit Any Inbound access list is 13
Switch# show ip interface f0/9 FastEthernet0/9 is down, line protocol is down Inbound access list is ip1
The only way to ensure that you can view all configured access groups under all circumstances is to use the show running-config privileged EXEC command. To display the ACL configuration of a single interface, use the show running-config interface interface-id command.
This example shows how to display the ACL configuration of Gigabit Ethernet interface 0/1:
Switch# show running-config interface gigabitethernet0/1 Building configuration…
Current configuration :112 bytes ! interface GigabitEthernet0/1 ip access-group 11 in snmp trap link-status no cdp enable end!
Examples for Compiling ACLs
For detailed information about compiling ACLs, refer to the Security Configuration Guide and the “IP Services” chapter of the Cisco IOS IP and IP Routing Configuration Guide for IOS Release 12.1.
Figure 12-2 shows a small networked office with a stack of Catalyst 2950 switches that are connected to a Cisco router. A host is connected to the network through the Internet using a WAN link.
Use switch ACLs to do these:
Create a standard ACL, and filter traffic from a specific Internet host with an address 172.20.128.64. Create an extended ACL, and filter traffic to deny HTTP access to all Internet hosts but allow all other types of access. Figure 12-2 Using Switch ACLs to Control Traffic
This example uses a standard ACL to allow access to a specific Internet host with the address 172.20.128.64.
Switch(config)# access-list 6 permit 172.20.128.64 0.0.0.0 Switch(config)# end Switch(config)# interface gigabitethernet0/1 Switch(config-if)# ip access-group 6 in
This example uses an extended ACL to deny traffic from port 80 (HTTP). It permits all other types of traffic.
Switch(config)# access-list 106 deny tcp any any eq 80 Switch(config)# access-list 106 permit ip any any Switch(config)# interface gigabitethernet0/2 Switch(config-if)# ip access-group 106 in
Numbered ACL Examples
This example shows that the switch accepts addresses on network 36.0.0.0 subnets and denies all packets coming from 56.0.0.0 subnets. The ACL is then applied to packets entering Gigabit Ethernet interface 0/1.
Switch(config)# access-list 2 permit 36.0.0.0 0.255.255.255 Switch(config)# access-list 2 deny 56.0.0.0 0.255.255.255 Switch(config)# interface gigabitethernet0/1 Switch(config-if)# ip access-group 2 in
Extended ACL Examples
In this example of using an extended ACL, you have a network connected to the Internet, and you want any host on the network to be able to form TCP Telnet and SMTP connections to any host on the Internet.
Switch(config)# access-list 102 permit tcp any 128.88.0.0 0.0.255.255 eq 23 Switch(config)# access-list 102 permit tcp any 128.88.0.0 0.0.255.255 eq 25 Switch(config)# interface gigabitethernet0/1 Switch(config-if)# ip access-group 102 in
SMTP uses TCP port 25 on one end of the connection and a random port number on the other end. The same port numbers are used throughout the life of the connection. Mail packets coming in from the Internet have a destination port of 25. Because the secure system behind the switch always accepts mail connections on port 25, the incoming services are controlled.
Named ACL Example
The Marketing_group ACL allows any TCP Telnet traffic to the destination address and wildcard 171.69.0.0 0.0.255.255 and denies any other TCP traffic. It permits any other IP traffic.
Switch(config)# ip access-list extended marketing_group Switch(config-ext-nacl)# permit tcp any 171.69.0.0 0.0.255.255 eq telnet Switch(config-ext-nacl)# deny tcp any any Switch(config-ext-nacl)# permit ip any any The ACLs are applied to permit Gigabit Ethernet port 0/1, which is configured as a Layer 2 port, with the Marketing_group ACL applied to incoming traffic.
Switch(config)# interface gigabitethernet0/1 Switch(config-if)# ip access-group marketing_group in …
Commented IP ACL Entry Examples
In this example of a numbered ACL, the workstation belonging to Jones is allowed access, and the workstation belonging to Smith is not allowed access:
Switch(config)# access-list 1 remark Permit only Jones workstation through Switch(config)# access-list 1 permit 171.69.2.88 Switch(config)# access-list 1 remark Do not allow Smith workstation through Switch(config)# access-list 1 deny 171.69.3.13
In this example of a numbered ACL, the Winter and Smith workstations are not allowed to browse the Web:
Switch(config)# accesslist 100 remark Do not allow Winter to browse the web Switch(config)# access-list 100 deny host 171.69.3.85 any eq www Switch(config)# access-list 100 remark Do not allow Smith to browse the web Switch(config)# access-list 100 deny host 171.69.3.13 any eq www
In this example of a named ACL, the Jones subnet is not allowed access:
Switch(config)# ip access-list standard prevention Switch(config-std-nacl)# remark Do not allow Jones subnet through Switch(config-std-nacl)# deny 171.69.0.0 0.0.255.255
In this example of a named ACL, the Jones subnet is not allowed to use outbound Telnet:
Switch(config)# ip access-list extended telnetting Switch(config-ext-nacl)# remark Do not allow Jones subnet to telnet out Switch(config-ext-nacl)# deny tcp 171.69.0.0 0.0.255.255 any eq telnet
Creating Named MAC Extended ACLs
You can filter Layer 2 traffic on a physical Layer 2 interface by using MAC addresses and named MAC extended ACLs. The procedure is similar to that of configuring other extended named access lists.
Note Named MAC extended ACLs are used as a part of the mac access-group privileged EXEC command.
Note Though visible in the command-line help strings, appletalk is not supported as a matching condition for the deny and permit MAC access-list configuration mode commands, nor is matching on any SNAP-encapsulated packet with a non-zero Organizational Unique Identifier (OUI).
Beginning in privileged EXEC mode, follow these steps to create a named MAC extended ACL:
Use the no mac access-list extended name global configuration command to delete the entire ACL. You can also delete individual ACEs from named MAC extended ACLs.
This example shows how to create and display an access list named mac1, denying only EtherType DECnet Phase IV traffic, but permitting all other types of traffic.
Switch(config)# mac access-list extended mac1 Switch(config-ext-macl)# deny any any decnet-iv Switch(config-ext-macl)# permit any any Switch(config-ext-macl)# end Switch # show access-list Extended MAC access list mac1 deny any any decnet-iv permit any any
Creating MAC Access Groups
Beginning in privileged EXEC mode, follow these steps to create MAC access groups:
This example shows how to apply ACL 2 on Gigabit Ethernet interface 0/1 to filter packets entering the interface:
Switch(config)# interface gigabitethernet0/1 Router(config-if)# mac access-group 2 in
Note The mac access-group interface configuration command is only valid when applied to an a Layer 2 interface. If applied to a Layer 3 interface, the interface must have been configured with an IP address.
For inbound ACLs, after receiving a packet, the switch checks the packet against the ACL. If the ACL permits the packet, the switch continues to process the packet. If the ACL rejects the packet, the switch discards the packet. The MAC ACL applies to both IP as well as non-IP packets.
When you apply an undefined ACL to an interface, the switch acts as if the ACL has not been applied to the interface and permits all packets. Remember this behavior if you use undefined ACLs as a means of network security.
I hope you found this article to be of use and it helps you prepare for your Cisco CCNA certification. I am sure you will quickly find out that hands-on real world experience is the best way to cement the CCNA concepts in your head to help you pass your CCNA exam!
Go to CiscoKits for your free Cisco Certification training. Cisco CCNA, CCNP, and CCIE training along with many options for Cisco home lab kits!
Software For Your Network Administration
Mar 3rd
Administrating a certain network can be exhausting if the personnel rely solely on their manual capabilities. Since administering a network is made possible because of advanced computer software, network management has become more sophisticated nowadays as more and more software is developed. Because of the series of advancement, administering a network increases the number of processes which are automated. Two of the automated processes done in network administration are network configuration and network analysis.
In a nutshell, network configuration refers to a process done through automation which offer several advantages in network administration. For one, it enables to decrease the time spent for doing tasks as well as the number of errors that might possibly happen while doing each task. Configuration consistency in multiple systems will also be increased through it. In addition, it provides a manner of process documentation.
Network configuration is made possible by several tools offered by several vendors. These products can be different in themselves since they possess distinct features that address certain network configuration concerns. Vendors such as AlterPoint, Gold Wire Technology, and Intelliden sell products that can store and keep track of servers, routers, and switch configurations. Companies such as Collation and Relicore sell products that can administer multiple devices in very efficient manner. Aside from these mentioned, there are other vendors that’s ell network configuration tools.
Network analyzer is a term applied to a computer software or hardware that can capture packets that run in any areas of the network and which to track their codes to be analyzed according to particular specifications. The alternative names of network analyzer are protocol analyzer, packet analyzer, and sniffer.
Network analyzer can hold up traffic on any other network areas depending on whether the LAN used is wired or wireless. Wired LANs do have the capability to intercept packets at any parts of the network. However, on wireless LANs, traffic can be held up only through a certain channel.
There are several software for network analysis in the market. The best selling software includes Carnivore, dSnif, Ettercap, Fluke Lanmeter, and Microsoft Network Monitor. What make these software best selling in the market are their most sought out features that include mechanism to detect network problems, detect network intrusions, collate and report network statistics, among others.
There are several vendors of network analyzers. The software can cost money, however, there are software that can be received for free. The web has a number of sites that offer both free and paid software. It is important to read reviews of each product before you select one so you can buy the best software in the market today.
Efficient network administration can only be made possible through the use of advanced software. Do not deprive your company of these software. Buy network configuration tools and network analyzers now!
Network Configuration relieves the jobs and workload of your Information Technology department. See how network analysis and management can help better your business.
How to Find Prank Caller That Irritates You
Feb 26th
Almost anyone of us have a landline and use a cell phone so as to communicate with all the people we are dealing with. A person may not have any other kind of luxury in his life but a cell phone and a cell phone is something each and every one of us owns because it helps us in connecting with people living in remote areas of the world.
Sometimes when we are sitting peacefully with people we love, some prank callers keep on calling our number and hang up number of times, it irritates us. It not only spoils of our private time but also annoys and frustrates us. You may have a caller ID to trace down the number from which a guy is calling but you couldn’t trace down his name and address using caller ID Service. Therefore it is crucial that you have such a service that can help you in locating the number, name and address of the guy who is calling you.
Today, you can definitely enjoy such benefits using the reverse phone detective service that helps you in finding out the details of the person who is on the phone. You just have to enter the phone number and you will get to know the type of the phone number, details of the owner of the phone number. Whenever you are cleaning up your house and come across with a number written on a piece of paper but are unable to recall whom it belongs to then you can use the reverse phone look up to know about the name of the owner of the phone number.
There are many facilities available to a human being since we are living in the 21st century where the technology keeps on advancing with every passing day. The reverse phone detective service is among the latest technology that is helping people to get in touch with their friends, relatives and even their classmates after several years. If you have forgotten the address of your close friend with whom you had loads of fun in your school time but have no contact with him now. Then you can just enter his phone number and learn about his contact details so that you can surprise him by dropping in his home.
There are many websites on the net that will help you in locating the address and other details of the phone number but many of the websites do not have cell phone numbers details. Most of the telemarketers get the access to the cell phone numbers of many people and keep on calling them again and again. In order to know what calls to pick you can use the reverse phone look up service to know what different numbers belongs to whom so that you can avoid picking them up and wasting your time.
If you’d like to know which reverse phone lookup service I recommended and specifically why, check out ReversePhoneDetective for a full in-depth review. You’ll see Why Private Investigators Are a Waste of Money, and how it can help you with that mysterious caller that is bugging the heck out of you!
CCNA & CCNP Lab Suggestions
Feb 24th
Many people ask me what would make a good CCNA lab? Well, that can be a tricky question based upon your budget and future Cisco aspirations. So let’s start off with a few basic concepts I hope we can all agree on. Real Routers
You need a physical router as the simulators just don’t have the ability to give you the “hands on” you need to see what happens when you disconnect a cable, put a cable in the wrong location or just plain configure the interface incorrectly. Dependant on what you do by mistake, you may see either the interface or protocol go down and based upon that it should give you a clue of where to start troubleshooting(hint, what layer is the interface at and what layer is the protocol at?). Anyway, you will come to find quite quickly that mistakes you make on Router 1 are affecting Router 4 all because you did not screw in a cable properly. No simulator can simulate that, so a router is invaluable.
I also get occasionally asked if someone can use their D-Link “router” or such in their lab. That class of home “router” generally does not support protocols such as RIP, OSPF, IGRP, etc. nor do they support the Cisco IOS which is a majority of the CCNA exam. So the answer is they are not really applicable to building your Cisco CCNA lab.
How Many Cisco Routers Do I Need?
Two routers really are required to see if anything works. If you have a very limited budget, you can receive value from only purchasing a single router over working with a simulator. However, you will not be able to see the main thing we are trying to accomplish. The propagation of route tables and the routing of data! The only way you can see if your configurations work, is to have at least two routers. That said, if you can afford a kit with more than two routers, it will enable you to exercise more complex scenarios. Therefore, I strongly recommend that you purchase a dual router kit or better that comes with all the accessories you need. Otherwise you can spend days or weeks trying to find all the little extra pieces you need to get your lab up and running. I mention this as some other resellers are selling their kits with 2500 routers and they are not including transceivers. Well how will you use the Ethernet AUI ports without them?? So this is basically how I view it. One router will give you the ability to run the commands on it and allow you to memorize the correct syntax and context in which to run the commands. Two routers will allow you to be able to see route table information propagate, data propagation and path election. In addition, you will see basic device elections. With three or more routers you will get all of the above and full device elections. Hopefully these tips will help you pick the right CCNA lab kit for you budget.
Can We Build A Lab That Will Cover Every Single CCNA Exam Concept?
We get this question quite often. Yes, we can, but it is not realistic for most customers who are self studying as this will cost well in excess of $5,000. If you have that sort of budget available, we suggest you pick on of the CCNP kits as that will get you through your CCNA exam and well on your way to your CCNP certification.
How Many Cisco Routers & Cisco Switches Do I Need To Complete Your CCNA Lab Workbook?
Our CCNA Lab Workbook was designed with the knowledge that most of our customers can’t afford a large lab. Keep in mind, that you will see a variety of labs that were written for three of four routers below. That does not mean you can’t complete most of them. It just for the most part means they will not be as complex as they could be.
Number of labs requiring only one router – 7
Number of labs requiring two routers – 11
Number of labs requiring three routers – 19
Number of labs requiring four routers – 4
Number of labs requiring one or more switches – 8
Now you can review the above link for our CCNA Lab Workbook to see all the topics covered. A physical copy of the Lab Workbook is included with our dual router or better kits. Now we have had a request by some customers who are not buying a full kit from us to just download a copy of the Lab Workbook or they want to preview the Lab Workbook. Well, we now offer a preview version of the Lab Workbook which you can download and view some of the labs and chapters. It is available at this link… CCNA Lab Workbook eBook Download Keep in mind, if you order the download version, you do not get a physical copy of the book. You only get a physical copy of the book if you order it from this link in which case it is shipped to you CCNA Lab Workbook. What Are Some Things I Need To Consider For My CCNA Lab?
Two new topics have popped up for the new Cisco CCNA 640-802 exam. They are IPv6(IP Version 6) and SDM(Security Device Manager) which is a GUI based way to configure your routers and switches. A common question is can the Cisco 2500 series routers support IPv6? Yes, they can if they are maxed out with 16MB of DRAM and Flash. Here are some more specs on Cisco routers and required DRAM and Flash to support IPv6 assuming you have the correct IOS. To make your life a little easier, I have included a handy chart illustrating the minimum DRAM and Flash required to support IPv6 per model platform below.
DRAM/Flash Memory Required for Feature Support
Model IPv6 SDM Max IOS Ver. Cisco 2500 16/16 Not Available 12.3 Cisco 2600 64/16 Not Available 12.3 Cisco 2600XM 128/32 128/32 12.4 Cisco 3620 64/16 Not Available 12.3 Cisco 3640 128/32 64/16 12.4 If you took a good look at the chart, you will also notice I mentioned the requirements for SDM too. As mentioned before, SDM is Cisco’s Security Device Manager and is the GUI option to configure your routers. It is not supported on some of the older models. But the good news from a lab perspective is that you do not need it on every router to get a good grasp on how SDM works. The Cisco 3640 router is going to be the cheapest way to get SDM with a 10mb Ethernet interface and the Cisco 2600XM series seems to be the cheapest way to get SDM with a 100mb Ethernet interface.
Finally, I also have an IOS version column. As you can see above, the Cisco 2500, 2600 and 3620 models only support 12.3 whereas the Cisco 2600XM and 3640 units support 12.4. So if you want to have exposure the latest IOS that is running on routers in the real world, right now that is 12.4. But if your budget does not allow for it, you will still find value in the routers that are running the older 12.3 IOS.
Why Do You Sell Routers With Memory That Can’t Run IPv6?
Not everyone has the budget to support every feature. So you will see that we still offer Cisco 2500 router kits with 8MB of DRAM and 8MB of Flash as being able to practice on routers that support 85% of the concepts is better than nothing at all if you budget is tight.
How Do I Know What Interfaces & Options Are Available On A Router?
In an effort to avoid any confusion and give you one place to look to compare models and interfaces/options, I made this next handy little chart to give you an idea of what to expect on each router.
Summary of Router Interfaces
Model Ethernet Sync Serial (DB-60) Async/Sync Serial Ports NM Slots Available Wan Slots Available Cisco 2501 1- AUI 10mb 2 0 0 0 Cisco 2503 1- AUI 10mb 2 0 0 0 Cisco 2507/16 16 Port Hub10mb 2 0 0 0 Cisco 2514 2- AUI 10mb 2 0 0 0 Cisco 2520 1- AUI 10mb 2 2 0 0 Cisco 2610 1- RJ-45 10mb 0 0 1 2 Cisco 2611 2- RJ-45 10mb 0 0 1 2 Cisco 2612 1- RJ-45 10mb 0 0 1 2 Cisco 2610/20XM 1-RJ-45 100mb 0 0 1 2 Cisco 2611/21XM 2-RJ-45 100mb 0 0 1 2 Cisco 1720 1- RJ-45 100mb 0 0 1 2 Cisco 2620 1- RJ-45 100mb 0 0 1 2 Cisco 2621 2- RJ-45 100mb 0 0 1 2 Cisco 3620 0 0 0 2 0 Cisco 3640 0 0 0 4 0 1 AUI = attachment unit interface. Anything Else You Can Suggest?
Well, a few things. The Cisco 2500s are serviceable routers for your CCNA studies still as long as you have the proper IOS and maxed out memory with all the accessories you need. You might say, but they are only 10mb routers. True, but they still work. The major drawback besides the aforementioned lack of SDM and 12.4 support is that with 10mb routers you can’t do your inter-vlan routing labs with them(which is true of any of the 10mb routers). So just make sure you have at least one 100mb router in your lab so you can do inter-vlan routing and that takes care of that issue and helps to keep the cost of your lab down for those with a tight budget!
You want to make sure your router can support IPv6 as doing those labs will really help the IPv6 concepts sink in. Finally, SDM is more than likely the wave of the future, so you might as well start to get used to it now!
What Is the CiscoKits Trade-Up Program?
In a nutshell something no other vendor is willing to offer to you! For any routers or switches you purchase from us, we will allow you to trade it in for a higher priced router or switch in the future as your Cisco certification lab grows. We are here to see you all the way up to CCIE as your Cisco certification partner! Please see the Trade-Up Program link on the left for full program details.
Do I Need A Switch?
This can be debated a few different ways. First some people will say that 80% of the test is based on routing. To which I will agree. But with only a small margin of error between passing and failing, not fully understanding switching concepts such as VLANs, STP, and root elections could be the one question that stands between you passing and failing your exam. There will be some switch questions which are memorization based such as “What is a Layer 2 protocol used to maintain a loop-free network?” Thank goodness we memorized STP. That said, it would be nice for us to be able to actually “see” the switching concepts work. So this is basically how I view it. One switch will give you the ability to run the commands on the switch and allow you to memorize the correct syntax and context in which to run the commands. It will also allow you to do some of the VLAN labs. Two switches will allow you to see VTP Domain & VLAN information propagate. In addition, you will see basic device elections. With three or more switches you will get all of the above and full device elections. Remember, we are only at the CCNA level right now so we will not need a Layer 3 switch like a 3550 just yet. But it is a cool concept of your CCNP studies. Finally you may ask why do some of my dual router kits not have switches in them. Well because you can quite simply go to the section on our site labeled Switches and add the switch you would like to be a part of your kit. The switches don’t need extra transceivers, ports and such so I don’t really have to kit them up with the routers. We do have some of the larger kits that have both routers and switches in them too.
What Switch Should I Get?
This is one that there is so much debate on these days. I will give you my thoughts on it and there are a hundred different ways you can build a lab. I will give you the information and let you decide how you want to build your lab.
The Cisco 2950 switch is the switch that is covered on the test and has the exact IOS command set that you will see on the lab. So if you can afford one, it is great to get. But sometimes when customers only have a $200 budget, I can’t suggest for them to get a switch and forego the routers. After all, the test is 80% routing! Back to the Cisco 2950, this is the best switch for the test if you can afford it.
But let’s say you can’t afford that switch , but still want a switch, what is next? We have the Cisco 2900 series. This is a step down from the Cisco 2950 and supports all the same CCNA test commands except the switchport and global vlan command. So with that knowledge, this switch may just work for you.
Finally, there is the Cisco 1900 series switches. There is not a lot of demand for these so they can be purchased very cheap. Some people say they have absolutely no value in a CCNA lab. I tend to disagree for the most part. You may ask me, hey, what are you smoking? The IOS that the Cisco 1900 series switches support is not the IOS that is on the test so how can it be useful? Well, let’s go into knowing that they IOS commands on the 1900 series are not the ones that are on the test. Ok, so we are not going to focus on them(remember, there are only a very few switch IOS commands on the CCNA exam in regard to syntax), but concepts that I find many people having a hard time understanding in how STP works, how the device elections are handled and such. Those concepts work exactly the same way on a 1900 as they do on the 2950 switch. Not to mention that you can do your VLAN, VTP and other similar labs on the switch to get an understanding on how they work. So hopefully you can see why I still carry them to help customers who are on a tight budget get exposure to such concepts. *Note, as of January 2009 the prices have come down on the 2900 series switches to the point it does not seem to be of great value for us to still carry the 1900 switches. The price between the two switch types is so close it is better to spend the extra few dollars and get a 2900 series switch.
As I did with the routers above, I have also included a switch feature chart below to help you make your Cisco switch selection.
Summary of Switch Features
Summary of Cisco Switch Features 1912/1924 2912/2924 2950 3550 Port Speed 10/100MB 100MB 100MB 100MB VLans X X X X Trunking X X X X Port Aggregation X X X X Mirroring X X X X ISL X X 802.1Q X X X QoS X X Layer 3 Switching X IOS Version 9.007 12.x 12.x 12.x
How to build your Cisco CCNP or Cisco CCIE Lab
Feel free to review our Cisco CCNP and Cisco CCIE Certification lab suggestion articles below:
Cisco CCNP Lab Suggestions
Cisco CCIE Lab Suggestions
Go to CiscoKits for your free Cisco Certification training. Cisco CCNA,CCNP,and CCIE training along with many options for Cisco home lab kits!
