(Message mtu:11) Date: Tue, 02 Dec 1997 01:05:54 +0100 From: Paolo Bevilacqua <"pab[remove_this]"@cisco.com> To: Rahul Dhesi Newsgroups: comp.dcom.sys.cisco cc: Franck@sopac.org.fj Subject: Re: Cannot reach sites with MTU<1500 X-Return-Path: "pab[remove_this]"@cisco.com X-Nojunk-Status: OK 0 X-Prev-Return-Path: "pab[remove_this]"@cisco.com X-Prev-Nojunk-Status: OK 0 Organization: cisco Systems X-Mailer: Mozilla 4.02 [en] (Win95; I) Mime-Version: 1.0 References: <880958743.6326@news.Colorado.EDU> <65ttqn$37e$1@samba.rahul.net> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Status: RO Rahul Dhesi wrote: > > In <880958743.6326@news.Colorado.EDU> Franck Martin > writes: > > [ dial-up PPP, MTU 576, can't reach some web sites ] > > >I set the MTU to 1500 and everything went fine. Please note that I did > >it at the same time as my ISP did it. > > >I wrote to the webmaster of these sites, and so far only one answered me > >letting me know that they use a cisco local redirector. > > I have observed similar problems. The problematic web site always seem > to be high-volume sites. And in my case too, one web site replied > saying it was using the Cisco local director. My workaround was to ask > users to go through a proxy server on the local network. > > I don't fully understand the problem. I tried tracing TCP/IP traffic > and found that the offending web sites were sending a packet with the DF > (don't fragment) bit set. It might be the case that the Cisco local > director is trying to do MTU discovery and something is failing. > -- > Rahul Dhesi LocalDirector software 1.6.4 should not have this problem. /pab -- Paolo Bevilacqua, Cisco Systems email: pab at cisco dot com