The problem is most likely MTU size. For some reason I still can't fathom, all Outlook/Exchange communications are sent with the Do Not Fragment bit set.
The problem is that going across a VPN reduces the MTU size available because of the encapsulation overhead. What's happening is that the client and server are incorrectly negotiating the MTU size, and then trying to communicate with packets that are too large to be tunnelled - but they're set to not fragment - and you have serious issues. Try running a network trace from an affected client, and you should see the errors. -------------------------------------------------------------- Roger D. Seielstad - MTS MCSE MS-MVP Sr. Systems Administrator Inovis Inc. > -----Original Message----- > From: Crista Murphy [mailto:[EMAIL PROTECTED] > Sent: Thursday, May 20, 2004 1:12 PM > To: Exchange Discussions > Subject: Latency Issue Exch03 - Outlook > > We have a large WAN with remote offices connecting to the > exch03 office > via PIX 501 to Sonicwall VPN. We are noticing severe latency > problems in > 90% of our remote offices when trying to use Outlook (2k std > & pro and XP) > which has shown up in conjunction with the move from the PIX > to PIX VPN to > the current configuration. > > Anyone have any suggestions on which diag logging to turn up > on the exch > server that might help diagnose this problem? The people in > charge of the > vpn's are 100% blaming the exch server for dropping sessions. > > Exch works fine in the local office and via webmail, it is only when > connecting thru the VPN with Outlook. > > Thanks! > > _________________________________________________________________ > List posting FAQ: http://www.swinc.com/resource/exch_faq.htm > Web Interface: > http://intm-dl.sparklist.com/cgi-bin/lyris.pl?enter=exchange&t ext_mode=&lang=english > To unsubscribe send a blank email to > %%email.unsub%% > Exchange List admin: [EMAIL PROTECTED] > To unsubscribe via postal mail, please contact us at: > Jupitermedia Corp. > Attn: Discussion List Management > 475 Park Avenue South > New York, NY 10016 > > Please include the email address which you have been contacted with. > _________________________________________________________________ List posting FAQ: http://www.swinc.com/resource/exch_faq.htm Web Interface: http://intm-dl.sparklist.com/cgi-bin/lyris.pl?enter=exchange&text_mode=&lang=english To unsubscribe send a blank email to [EMAIL PROTECTED] Exchange List admin: [EMAIL PROTECTED] To unsubscribe via postal mail, please contact us at: Jupitermedia Corp. Attn: Discussion List Management 475 Park Avenue South New York, NY 10016 Please include the email address which you have been contacted with.
