Cisco IP Debuggin Not Working

Posted on 2004-08-09
Last Modified: 2012-05-05
I am having problems getting DEBUG IP ICMP to work on my 7507.  This router have one fast ethernet interface and several serial interfaces as it serves as my frame relay router.

I have made sure that my NO IP ROUTE-CACHE command is applied to the interface that the packets I want to watch are comming from, but still no luck.  I have also tried applying an access list to no avail.

I'm just trying to ping between two 7507 routers.  

This is causing me to not be able to troubleshoot a routing issue right now on my backbone.

Question by:TroyGA
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 3
  • 2
  • 2
  • +1
LVL 79

Expert Comment

ID: 11758166
Are you using a telnet session, or straight on the console port?
If using telnet, issue "term mon" command

Author Comment

ID: 11758562
Forgot to add that in ; yes using a telnet session with the following commands:

debug ip icmp
ter mon

LVL 79

Expert Comment

ID: 11758630
Industry Leaders: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!


Author Comment

ID: 11762250
I looked over the two articles listed here and have tried everything suggested.

Not using CEF or any other fast switch mechanisms.

It's just not working =/

Expert Comment

ID: 11800685
In order to have your debugging messages appear in a console, you need the following:
1) Define target logging level:
    Level       Keyword       Description
    0         emergencies   System is unusable.
    1         alerts             Immediate action is needed.
    2         critical            Critical conditions exist.
    3          errors            Error conditions exist.
    4          warnings        Warning conditions exist.
    5          notification     Normal, but significant, conditions exist.
    6          informational  Informational messages.
    7          debugging      Debugging messages.
2) Define where you want to output logs: console, monitor (telnet session) or syslog
3) Configure logging:
    config t
    logging console <logging level>   <----if you want logging to serial port console
    logging buffered                         <----if you want logging to telnet monitor
    logging monitor <logging level>
    logging <ip address>                  <----if you want to log to syslog
    logging trap <level>
4) To see actual monitor logs, "term mon" at telnet session.

In your case:
logging buffered
logging monitor debug
term mon
debug ip icmp


Author Comment

ID: 11802070
I wish I could say that worked but again, nothing is happening =(

Expert Comment

ID: 11802855
A few things to check:
1) Configure "logging on";
2) If you are doing conditional debugging ("debug interface"), make sure you selectec the "right" interfaces, or just do "no debug interface" or "no debug interface all" to reset it;
3) If you are using conditional debugging, double check "debug condition" command nesting.
LVL 28

Expert Comment

ID: 11854343

I have had a similar problem sometimes and I never figured out why. You should definitely be able to do it with an access list. for example if you created the following access list and applied it both inbound and outbound, you should see every icmp packet logged:

access-list 100 permit icmp any any log
access-list 100 permit ip any any

All that logging stuff from earlier has nothing to do with whether you will see the debug output, it only affects how it logs the debug. If you set "term mon" in your vty session you will see it. On the console you have to set "logging console" but this is on by default.
LVL 28

Accepted Solution

mikebernhardt earned 500 total points
ID: 11854371
By the way, the above doesn't rely on debug at all- it's just logging packets. And a correction- if you want to see the logging messages in your term mon then you need to configure "logging level debug"

apply the access list to the appropriate interface with
access-group 100 in
access-group 100 out

Featured Post

Save the day with this special offer from ATEN!

Save 30% on the CV211 using promo code EXPERTS30 now through April 30th. The ATEN CV211 connects a laptop directly to any server allowing you instant access to perform data maintenance and local operations, for quick troubleshooting, updating, service and repair.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
Cisco Router DMZ 5 92
Vlan to Vlan communication 9 124
Best adsl router for small MS network 6 72
Cisco router is restricting wireless bandwidth download and upload speed 38 51
Tired of waiting for your show or movie to load?  Are buffering issues a constant problem with your internet connection?  Check this article out to see if these simple adjustments are the solution for you.
Creating an OSPF network that automatically (dynamically) reroutes network traffic over other connections to prevent network downtime.
After creating this article (, I decided to make a video (no audio) to show you how to configure the routers and run some trace routes and pings between the 7 sites…
After creating this article (, I decided to make a video (no audio) to show you how to configure the routers and run some trace routes and pings between the 7 sites…

726 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question