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upgrading IOS on Cisco routers and switches is hightly recommendable because of the following reasons

Patch critical vulnerabilities: Just like any other network device or application, Cisco routers and switches are also prone to security holes. And because routers and switches are critical to network infrastructure, you should plug these security holes as soon as possible.

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Read the rest of Upgrade Cisco IOS in a Router or a Switch (385 words)

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upgrading IOS on Cisco routers and switches is hightly recommendable because of the following reasons

Patch critical vulnerabilities: Just like any other network device or application, Cisco routers and switches are also prone to security holes. And because routers and switches are critical to network infrastructure, you should plug these security holes as soon as possible.

(...)
Read the rest of Upgrade Cisco IOS on Router and Switche (385 words)

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If you want to ensure that only a certain device—for example, a server—is plugged into a particular switch port, you can configure the MAC address of the server as a static entry associated with the switch port.

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Read the rest of Setting Port Security on a Cisco Catalyst Switch (290 words)

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OpManager is a network monitoring software that can automatically discover your network; group your devices into intuitive maps, monitor devices in real-time and alert instantaneously on failure. It serves as a complete network monitoring solution by providing complete fault and performance functionality across your WAN and LAN infrastructure.

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Read the rest of Monitoring Servers,Network Devices with Opmanager (396 words)

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This ‘How to’ is written to show the step by step password recovery of the Cisco Routers. It is assumed that you have a prior knowledge of what a router is and its basic function. It is also assumed the you are having some experience of configuring the router.

Please do not follow these steps if you are a new to Routers, as this can damage the IOS or any physical interface of the router.

1.Connect a computer to the router’s Console port using the Console cable that came with your router (it is usually flat and light blue).

Use these terminal settings:
* 9600 baud rate
* No parity
* 8 data bits
* 1 stop bit
* No flow control

2.Turn the router off using the power switch and turn it back on.

3.Once text starts popping up on the screen, send the break command CTRL + B or CTRL +BREAK (sometimes it is CTRL +X). This will abort the boot and present you with a rommon 1> prompt

4.From the new prompt you need to change the configuration register using the following command: confreg 0×2142

5.If you are using an older model of router you may need to enter o/r 0×2142

6.Now you need to recycle the router with the reset command.

7.If you used the o/r command then reset the router with the I command

8.Once the router finishes restarting you will find that there are no passwords to deal with, so you can enter enabled mode carte blanche.

9.Once in enabled mode enter this: copy start run. This will copy the startup config to the running config.

10.Now, go into configuration mode with the config t command

11.Once there enter the new password with the enable secret password command (i.e. enable secret admin).

12.Now set the configuration register back to normal with this command: confreg 0×2102

13.Exit config mode and enter the command copy run start to copy the new configuration to ram.

14.Now it is time to reload your router

15.Once the router is back up you need to configure all of your interfaces with the no shutdown command or they will not work.

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Layer 2 switch is A network device that forwards traffic based on MAC layer (Ethernet or Token Ring) addresses.

Bridging technology has been around since the 1980s (and maybe even earlier). Bridging involves segmentation of local-area networks (LANs) at the Layer 2 level. A multiport bridge typically learns about the Media Access Control (MAC) addresses on each of its ports and transparently passes MAC frames destined to those ports. These bridges also ensure that frames destined for MAC addresses that lie on the same port as the originating station are not forwarded to the other ports. For the sake of this discussion, we consider only Ethernet LANs.

Layer 2 switches effectively provide the same functionality. They are similar to multiport bridges in that they learn and forward frames on each port. The major difference is the involvement of hardware that ensures that multiple switching paths inside the switch can be active at the same time.

There are three distinct functions of layer 2 switching

1)address learning

2)forward/filter decisions

3)loop avoidance

Address learning

Layer 2 switches and bridges remember the source hardware address of each
frame received on an interface, and they enter this information into a MAC database called a forward/filter table.

Forward/filter decisions

When a frame is received on an interface, the switch looks at the destination
hardware address and finds the exit interface in the MAC database. The frame is only
forwarded out the specified destination port.

Loop avoidance

If multiple connections between switches are created for redundancy purposes,
network loops can occur. Spanning Tree Protocol (STP) is used to stop network loops
while still permitting redundancy.

©2008 Debian Admin. All Rights Reserved.

There are five passwords used to secure your Cisco routers: console, auxiliary, telnet (VTY),enable password, and enable secret. Just as you learned earlier in the chapter, the first two passwords are used to set your enable password that’s used to secure privileged mode. This will prompt a user for a password when the enable command is used. The other three are used to configure a password when user mode is accessed either through the console port, through the auxiliary port, or via Telnet.

Setup Enable Passwords

You set the enable passwords from global configuration mode like this

Router(config)#enable ?

last-resort - Define enable action if no TACACS servers respond

password - Assign the privileged level password

secret - Assign the privileged level secret

use-tacacs - Use TACACS to check enable passwords

The following points describe the enable password parameters

Last-resort - Allows you to still enter the router if you set up authentication through a TACACS
server and it’s not available. But it isn’t used if the TACACS server is working.

Password - Sets the enable password on older, pre-10.3 systems, and isn’t ever used if an enable
secret is set.

Secret - Is the newer, encrypted password that overrides the enable password if it’s set.

Use-tacacs - This tells the router to authenticate through a TACACS server. It’s convenient if you
have anywhere from a dozen to multitudes of routers.

Here’s an example of setting the enable passwords

Router(config)#enable secret admin

Router(config)#enable password admin

The enable password you have chosen is the same as your enable secret. This is not recommended. Re-enter the enable password.

If you try to set the enable secret and enable passwords the same, the router will give you a nice, polite warning to change the second password. If you don’t have older legacy routers,don’t even bother to use the enable password.

©2008 Debian Admin. All Rights Reserved.

You can set the identity of the router with the hostname command. This is only locally significant,which means that it has no bearing on how the router performs name lookups or how the router works on the internetwork.

Here’s an example

Router#config t

Enter configuration commands, one per line. End with
CNTL/Z.

Router(config)#hostname debianadmin

debianadmin(config)#hostname london

london(config)#

Even though it’s pretty tempting to configure the hostname after your own name, it’s definitely a better idea to name the router something pertinent to the location. This is because giving it a hostname that’s somehow relevant to where the device actually lives will make finding it a whole lot easier. And it also helps you confirm that you are, indeed, configuring the right device.

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