[130031] in North American Network Operators' Group
Re: large icmp packet issue
daemon@ATHENA.MIT.EDU (ML)
Sun Sep 26 10:50:05 2010
Date: Sun, 26 Sep 2010 10:49:48 -0400
From: ML <ml@kenweb.org>
To: nanog@nanog.org
In-Reply-To: <AANLkTi=RBjTQMZf2m1_N4hd8B2PZFs01TecrF1aM_P7Y@mail.gmail.com>
Reply-To: ml@kenweb.org
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
On 9/25/2010 10:57 PM, fedora fedora wrote:
> I am having problem getting ping to work to a specific destination host when
> using large size icmp packet and i am hoping someone here can offer some
> suggestion.
>
> With regular ping, i can ping this remote host without any problem, but if i
> crank up the packet size to above 1500 (1500 still works), i won't get any
> icmp reply.
>
> My first thought was this was a pmtu issue. but when I ran tcpdump on this
> remote host, i saw the incoming ping requests and this host actually sent
> back icmp replies, so it appears that there is some device in between
> blocking these large size icmp reply packets.
>
> Here is the question, how can i find out which hop on the path is causing
> this behavior?
>
> FD
Can you provide a pcap file?
