TCPDUMP in CISCO Routers 2

[Yehey]

Hi all,

Is there a command to view incoming/outgoing packets in a cisco router? Just like "tcpdump" in linux.


Thanks.

 

[burtsbees]

debug ip packet
Also, ip accounting output-packets and ip route-cache configured on a particular interface, and the show commands associated with those two...sh ip account and sh ip cache flow.

Burt

 

[brianinms]

I would be very careful running this command on a router in production as it can easily lock the router up.

 

[burtsbees]

Oh---the debug ip packet? That's true. Thanks brian---I should have mentioned that.

Burt

 

[lerdalt]

This isn't exactly what you are asking for, but check this out:

http://networkinginstyle.blogspot.com/2008/02/how-to-perform-packet-capture-on-cisco.html

Also with the debug ip packet command you do need to be careful with it...I've always found it a good idea to have a second telnet session open to the router with the undebug all command ready to go.

But another tip, use an ACL with the debug ip packet command to kind of filter out what you are trying to look at.

 

[burtsbees]

Wow...but that's a newer command feature. It says it was introduced on 12.4(11) on 1800, 2800 and 3800 platforms...I have advanced enterprise 12.4(9) on a 2620XM, and it works...very interesting and useful command, lerdalt. Have a star.

Burt

 

[lerdalt]

I haven't had a chance to try it out. Have you done much with it? I'm bummed it's not on the 6500 or 7200 platforms.

 

[burtsbees]

No, not yet. Too busy...*AHEM*...(lazy)...lol

 

[Yehey]

Thanks all for the reply.

Tried the debug ip packet command and my router almost
hanged.