Debug command

[PietroPoliseno27977]

Hi everyone I am not clear how to use the debug command. In the book cisco it says: Once you issue a debug command, IOS remembers,
issuing messages that any switch user can choose to see. When I run for example on a cli switch debug ip icmp gives me as a result only: "icmp packet debugging is on" why? Shouldn't he have shown me some ongoing operations?

[Reza Sharifi]

Hi,

Turning on debug commands without specifying exactly what you need can be harmful, bring down the switch and cause an outage.

So, when you turn on icmp packet debugging, it only provides reports on ICMP and nothing else. What else are you looking for?

HTH

[PietroPoliseno27977]

I am studying for ccna. I ran this command on a 2900 cisco packet tracer switch. I just wanted to see what it displayed. Shouldn't it display icmp activities? I only get the message "icmp packet debugging is on". I am not looking for anything in particular it was for training purposes

[Reza Sharifi · Accepted solution]

Go it. Ok, so when you get "icmp packet debugging is on". means ICMP is turned on. So, now if you ping an IP address on the switch or you ping a device from the switch, you should see the debug messages on the screen. If you don't see them, try this command. 'terminal monitor".

I am not familiar with packet tracer. So, things may or may not work the same way as a regular switch.

HTH

[PietroPoliseno27977 · Accepted solution]

I pinged like you just told me messages guess where they appear?Not on the switch but on the router connected to the switch. I have this situation Router A connected to switch A. On switch A I have 4 hosts; I pinged from a .7 host to a .8 host icmp messages do not appear on the switch where i have enabled debugging but do appear on the router. What program do you use for simulations? I don't want it to be a packet tracer defect

[Reza Sharifi]

So, in order to see the messages, there needs to be an IP address configured on the switch. That is probably the reason that you see them on the router but not the switch.

I use real equipment but have heard that VIRL is much better for simulation than PT. Have a look at this link and enjoy studying!

https://learningnetworkstore.cisco.com/virlfaq/

HTH

[Reza Sharifi]

And one more, which is free (none professional) and I hear it is very good. You can do almost everything with the free version.

https://www.eve-ng.net/

HTH