Put a label on static routes

In the unfortunate case of having to use static routes it can be useful to put a label on each route describing the purpose so that if there is ever the opportunity to remove the route it is clear as to it's purpose. On Cisco routers the syntax is as follows:

router(config)# ip route x.x.x.x y.y.y.y z.z.z.z name (name)

Where X = the IP address and Y = the subnet mask and Z = next hop. The name can't have any spaces. For example:

router(config)# ip route 10.1.1.1 255.0.0.0 10.1.1.2 name production_static_route

Cisco module reboot

The Cisco chassis-based switches will allow a reboot of a single module versus reloading the entire switch or reseating the module physically. This can be helpful for remote troubleshooting or to prevent interruption to the remainder of the switch caused by a device reboot. The IOS command syntax is as follows:

switch# hw-module module (mod #) reset

Reload in N minutes

Use the Cisco router enable mode command 'reload in N' where N=the number of minutes after pressing enter following this command that the router will reload. For example:

router#reload in 5

The above command will reload the router in 5 minutes. The command seems trivial but consider the scenario where you are configuring a remote router and lose connectivity due to a misconfiguration. If you were able to enter the command ahead of time then the router would reboot in the specified number of minutes and your configuration would be restored, allowing reconnection.

Cisco "full-help" command - View invisible help commands

The Cisco "full-help" command can be used to display a list of help commands that may not be present when simply typing "show ?" in user mode. There are additional help commands that can be displayed in user mode by first typing "terminal full-help". Once that is complete run a "show ?" and take note of the additional command options. This can also be controlled at the line level using the "full-help" command.

The Cisco pipe command - filter for portions of the configuration

The Cisco pipe command is particularly useful when you need to display subsets of rather long configurations or when you need to key in on a particular point in the configuration. The pipe command is put to use by using the pipe symbol following the show command to filter for anything beginning (the "begin" switch) with a certain point in the configuration or including (the "include" switch) certain information. The switches are similar to the Unix file management "head", "tail", and "grep" commands only they produce slightly different results. The begin switch produces configuration output starting with the pipe begin query. The include switch produces configuration output only including the pipe include query. The ouput in either case will produce a line of configuration at a minimum that corresponds to the query. Multiple include queries can be concatenated to filter for several parameters. Below are some examples.
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To show running configurations for interfaces and their associated IP addresses:
show run (pipe) inc interface (pipe) ip address
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To show serial interfaces:
router# show interfaces (pipe) beg Serial

Cisco "do" - save yourself from backing out to run commands

The Cisco "do" command allows you to run privileged commands on a router or switch from the global configuration mode or greater (such as interface) without having to back out to privileged mode. The advantage of using this command is that you can use it to run commands that are basically out of context. To run this command you must be running IOS version 12.2(8) or later. It enables the use of show, ping, clear, and debug. An example:

router(config)# do show interface gi0/1
switch(config-if)#do show run

Purpose of this blog

This blog is dedicated to the sharing of tips, tricks, and design ideas for configuring networks.