Was chatting with Darren at Darren’s CCIE mission yesterday. We started to discuss some of the commands we frequently used to check IP addresses etc. He thought I should do a post on it and here it is.

This first one I stumbled upon when I was going to type show ip prot but accidentally typed show ip port which turned out to be a good thing. This command show port mappings for different protocols used by IOS. If we get a task on lab to do filtering and can’t remember the port this can be really useful.

As you can see we can do an include to match on a port number or a protocol name.

The next command is one of the commands I use the most, show ip int brief | ex una. This will list all interfaces that have an IP address configured.

This is good but it will not tell us the netmask. If we have a troubleshooting task it is nice to check what IP’s are configured and if the correct netmask is used. Wit the next command we can check the netmask. Show ip int | i Internet.

If I want to verify reachability quickly I need to list all IP address configured on the devices. I use the show ip aliases command to do this. I paste the command in including a line feed on all devices and then hold alt down while I mark all the adresses.

I then put these addresses in a simple TCP script like below:

tclsh
foreach ip {
1.1.1.1
2.2.2.2
3.3.3.3
} { ping $ip}

This post should give you some tips on how to quickly discover IP addresses configured.

Useful commands for CCIE lab exam
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7 thoughts on “Useful commands for CCIE lab exam

  • July 27, 2011 at 9:25 am
    Permalink

    Hi Daniel,

    I believe the command you are looking for is show protocol.

    show protocol

    Global values:
    Internet Protocol routing is enabled
    FastEthernet0/0 is up, line protocol is up
    Internet address is 155.1.146.1/24
    Serial0/0 is up, line protocol is up
    Internet address is 155.1.0.1/24
    FastEthernet0/1 is administratively down, line protocol is down
    Serial0/1 is up, line protocol is up
    Internet address is 155.1.13.1/24
    Loopback0 is up, line protocol is up
    Internet address is 150.1.1.1/24

    Using this command you can check both the IP address and mask assigned to each interface.

    Reply
  • July 27, 2011 at 9:55 am
    Permalink

    Hi Tommey,

    Never used that command. That is a good command. Quick way to see if routing is enabled.

    R1#show prot | ex down|up
    Global values:
    Internet Protocol routing is enabled
    Internet address is 1.1.1.1/24
    Internet address is 2.2.2.2/24

    This will show a good summary of adresses and if routing has been enabled.

    Reply
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  • July 30, 2011 at 2:23 pm
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    Wow you guys are awesome to blow these reminders into our ears again…thumbs up!!!

    Reply
  • July 31, 2011 at 6:18 pm
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    Daniel
    you probably know this one already but the SECTION command is very useful
    for instance show run | section (anything here to have a limited but precise view of what you need) or show ip protocols | section ? .It is better than | begin because there is less to see on the screen.It has many different applications it is worth a try.

    Reply
  • April 26, 2012 at 12:10 pm
    Permalink

    I agree with section command but it doesn’t work with Catalysts 3560 running 12.2 version…

    Reply
    • April 26, 2012 at 12:48 pm
      Permalink

      No, for some reason Cisco has not implemented that on Catalysts. The best you can do is to do show run | b router ospf or similar.

      Reply

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