Why can't I see NTP traffic passing through my router using debug?

Posted on 2008-10-16
Medium Priority
Last Modified: 2012-05-05
I am troubleshooting NTP issues between my server and outside time providers.  When I turn on debug using "debug IP UDP" on the router, I see some UDP traffic, but no NTP.  When I sniff on the vlans, I do see the NTP packets on both sides of the router.  Can someone please explain why the NTP packets won't show up on my router's debug output?  Is it something I need to do on the router?  Thank you.  
Question by:altonyoung
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
  • 2

Accepted Solution

RSLE earned 375 total points
ID: 22733899
are you sure your using NTP and not some other time protocol?

maybe there's an ACL on the router or a firewall on you server blocking it before it gets to the router?
LVL 44

Assisted Solution

Darr247 earned 375 total points
ID: 22737350
Are you watching port 123?

Author Comment

ID: 22738020
Thank you both for getting back to me.  

1.  I am sure it is NTP.  I can see the NTP traffic (UDP port = 123) when I sniff the traffic on the vlans using Wireshark.  

2.  I know the NTP packets passed the routers because I can follow them from the source all the way to the default router.   I just don't know why these particular NTP traffic won't show on the router when I use debug.  These are no ACLs applied to the routers.  

Any more ideas?    


Author Closing Comment

ID: 31506827
Never figured it out, but will award the points anyway since they tried.  

Featured Post

[Webinar] Lessons on Recovering from Petya

Skyport is working hard to help customers recover from recent attacks, like the Petya worm. This work has brought to light some important lessons. New malware attacks like this can take down your entire environment. Learn from others mistakes on how to prevent Petya like worms.

Question has a verified solution.

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

The Cisco RV042 router is a popular small network interfacing device that is often used as an internet gateway. Network administrators need to get at the management interface to make settings, change passwords, etc. This access is generally done usi…
There are two basic ways to configure a static route for Cisco IOS devices. I've written this article to highlight a case study comparing the configuration of a static route using the next-hop IP and the configuration of a static route using an outg…
After creating this article (http://www.experts-exchange.com/articles/23699/Setup-Mikrotik-routers-with-OSPF.html), 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 (http://www.experts-exchange.com/articles/23699/Setup-Mikrotik-routers-with-OSPF.html), 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…
Suggested Courses

765 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