nanog mailing list archives
Re: large icmp packet issue
From: Robert Bonomi <bonomi () mail r-bonomi com>
Date: Sat, 25 Sep 2010 22:18:07 -0500 (CDT)
From nanog-bounces+bonomi=mail.r-bonomi.com () nanog org Sat Sep 25 21:56:30 2010 Date: Sat, 25 Sep 2010 21:57:53 -0500 Subject: large icmp packet issue From: fedora fedora <fedorafans () gmail com> To: nanog () nanog org 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?
Did you consider doing a traceroute? And then pinging the intermediate machines? with the big packets, that is. you'll get a response from the 'near side' of the problem, but -not- from any machine on the far side of it. Ping with small packets first, to discovr machines that dont respond to pings at all.
Current thread:
- large icmp packet issue fedora fedora (Sep 25)
- Re: large icmp packet issue ML (Sep 26)
- <Possible follow-ups>
- Re: large icmp packet issue Robert Bonomi (Sep 25)
- Re: large icmp packet issue fedora fedora (Sep 25)
- Re: large icmp packet issue Heath Jones (Sep 26)
- Re: large icmp packet issue fedora fedora (Sep 25)