large icmp packet issue

Sun Sep 26 02:57:53 UTC 2010

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