Five tips for Cisco IOS Configuration

Cisco's Internet Operating System IOS) is a complex operating system optimized for the Internet. There are many IOS skills on the Internet, but most of the best skills are not enough to form a complete article. Today, I want to use one of the Chinese IT labs to describe five tips for using Cisco IOS. I believe these skills will definitely make the network administrators work more efficiently.

Tip: simplify command input

It can be asserted that almost any Network Manager using Cisco IOS knows clearly that IOS can accept the minimum characters (letters) representing a valid IOS command ). However, I noticed that some administrators are still typing complete commands or entering more letters.

If we accumulate the time spent on inputting these unwanted letters, we will see an amazing result. The following are examples of simplified use:

1. show ip route = sh ip ro

2. show running-configuration = sh run

3. show ip ospf = sh ip o

In this case, why don't we use the simplest command to complete the work? Instead of using copy running-configuration startup-configuration or co run start, use wr. In fact, the old write command can complete the same task, but it is obvious that the numbers of letters to be entered vary greatly!

In fact, there are better methods. Use these short commands for aliases. For more information, see the following article "Enter commands more efficiently with Cisco command aliases.

Tip 2: Let time serve you

In many cases, a router event occurs quickly and quickly, so that multiple events sometimes occur at the same time (especially on a large router with a large number of routes ). To ensure that the router log can accurately tell you what happened, you can use this command:

The following is a reference clip:
Service timestamps log datetime localtime show-timezone msec year

This command ensures that the vro prints log information based on the current time, time zone, millisecond, and year when an event occurs.

The following is what the time stamp looks like (no year ):

The following is a reference clip:
* Oct 21 15:31:54. 955 CDT: % LINEPROTO-5-
UPDOWN: Line protocol on Interface GigabitEthernet0/0, changed state to down

In addition, you can use the service sequence-numbers command to include an absolute logarithm that confirms each event and displays the sequence of events. Enter this command to tell the router to add a number to a record message, so that the event is confirmed and the sequence of the event is indicated by a limited serial number.

Tip 3: "reproduce yesterday" or "change yourself"

As a network manager, you may often encounter this situation: you have configured an interface on the router today and want to reconfigure it the next day. In fact, we do not need to use a single command to clear the settings, and we do not have to consider what commands are added and what are the default values, we can use a command to quickly restore an interface to the default value. You only need to use the default interface command, such as default interface Fa0/0.

Tip 4: change the filter

Linux administrators know how to use grep for filtering. I am confused that some Cisco network administrators are still browsing a large number of running configurations when they know what to look.

These administrators can save a lot of trouble. The next time they look for something in Cisco's IOS command output, they can use begin or include. For example, to start an OSPF configuration, you can use sh run | beg router ospf. To display all the ip address configurations on a vro, use sh run | inc ip address.

In fact, you can also use exclude. We can assert that there are a lot of ways to use these command filtering techniques.

Tip 5: do

Many network administrators constantly switch from the global mode to the privileged mode, and then return to the global mode for different configurations. This may be a habit of many people. Maybe we are learning how to configure IOS, as if we are used to switching from "configuration mode" to "display mode ".

Now it's time to change the old habits. To save time, you must start by using the "do" command. This command allows the Administrator to run the privileged mode command in global configuration mode. What's even more, it takes a very short time, completely different from the original tedious method: first return to the privileged mode, enter the command, and then enter the global configuration mode.

What the administrator needs to do is to use the do command before the command. With this command, you can execute any executable privileged mode commands in the global configuration mode prompt.

For example, you want to configure OSPF and check whether the online neighbors are online. The example command is as follows:

The following is a reference clip:
Router (config) # router VPN 100
Router (config-router) # do sh ip ei nei
IP-EIGRP neighbors for process 100
H Address Interface Hold Uptime srtt rto q Seq
2 12.1.1.2 Fa0/0 13 00:52:47 88 2280 0 6581

Summary

To do well, you must first sharpen your tools. Finding a more effective way of working is always very important. These five skills can help you complete the same task that you are currently doing. However, because you have adopted some commands that you may not be concerned about, the operations are more concise and clear. Try again.