Router / Protocol Problem

Matthew Crocker matthew at crocker.com
Wed Sep 6 14:09:54 UTC 2006


Does your peer or you have any ACLs on the PtP link which may be  
dropping the packets? If your peer is doing uRPF and doesn't have  
your route properly installed it can cause problems on their edge.

Are the sites you cannot reach akamaized?  I've had issues with some  
akamaized sites when I was being redirected to akamai servers that  
weren't on my network. Do a dig on the website and see if it returns  
an akamai server

Is there any packet loss/CRC errors on the link to your peer?   A  
noisy line will affect large packets more than small packets, I've  
had issues where only the text/CSS of a website would come up but the  
images would not.

Any MTU issues?  Same as above,  MTU issues causing large packets to  
get dropped and no images on websites.

Pings, traceroute,telnet all work in those cases

-Matt


On Sep 6, 2006, at 9:04 AM, Mike Walter wrote:

> I normally would not post to the group, but I am 100% stumped and  
> have talked with peers with no luck.
>
> I have (2) Cisco 7204 Routers running BGP with 3 peers and HSRP.  I  
> am not doing anything special with BGP, pretty much a default  
> config that has not changed in years.
>
> Recently with no changes to my network, I have been having problems  
> connecting to certain websites and mail servers.  I am always able  
> to ping the sites and trace route without error.  If I telnet to  
> port 80 or port 25 it does not connect.  If I login to my router  
> and telnet sourcing my each of Internet Providers ports, I am able  
> to get to the sites.  I have talked with all the providers and none  
> can find a problem.  If I shut down one specific peer, everything  
> works fine.  So I keep thinking it was that peers problem some  
> how.  I have tested with just that peer up and I still can not  
> connect.  However, when talking with that peer, they are able to  
> telnet from their network to the sites I can not reach.  I don't  
> know what else to check besides shutting down that peer.  Which  
> since it is under a 3 year contract, not an option.  That isn't the  
> real solution anyhow.
>
> Can anyone shed some light on or off-list?
>
> Thanks,
>
> Mike Walter
>

--
Matthew S. Crocker
Vice President
Crocker Communications, Inc.
Internet Division
PO BOX 710
Greenfield, MA 01302-0710
http://www.crocker.com




More information about the NANOG mailing list