Well, the problem is resolved but nobody's entirely sure how. It looks like it was an issue with a router somewhere upstream discarding improperly sized packets instead of responding properly (Q136970 is sort of related) but whose router and what they did to fix it we don't know for certain just yet.
What a day. -Ben- Ben M. Schorr, MVP-Outlook, CNA, MCPx3 Director of Information Services Damon Key Leong Kupchak Hastert http://www.hawaiilawyer.com > -----Original Message----- > From: Ben Schorr [mailto:[EMAIL PROTECTED]] > Sent: Tuesday, March 19, 2002 1:00 PM > To: Exchange Discussions > Subject: Some "Hosts Unreachable" > > > This is a new one on me; maybe some of you have seen it > before. Exchange 5.5 on NT4SP6a using the IMS to connect > through an ISA server. On a handful of hosts the message > queues up with a "Host Unreachable" error. On most hosts > (including old favorites like aol.com, hotmail.com, etc.) > mail comes and goes just fine and we don't seem to be having > any problems RECEIVING mail. > > But to this small band of hosts (including hawaii.edu and > hawaii.rr.com) the mail just queues up. Here's a snippet > from an SMTP log that may shed some > light: > > 3/19/02 12:15:06 PM : >>> MAIL > FROM:<[EMAIL PROTECTED]> SIZE=1977 RET=FULL > 3/19/02 12:15:06 PM : <<< IO: |250 2.1.0 > [EMAIL PROTECTED] OK > | > 3/19/02 12:15:06 PM : <<< 250 2.1.0 > [EMAIL PROTECTED] OK > 3/19/02 12:15:06 PM : >>> RCPT TO:<[EMAIL PROTECTED]> > NOTIFY=FAILURE,DELAY > > 3/19/02 12:15:06 PM : <<< IO: |250 2.1.5 [EMAIL PROTECTED] > | > 3/19/02 12:15:06 PM : <<< 250 2.1.5 [EMAIL PROTECTED] > 3/19/02 12:15:06 PM : >>> DATA > > 3/19/02 12:15:06 PM : <<< IO: |354 Start mail input; > end with <CRLF>.<CRLF> > | > 3/19/02 12:15:06 PM : <<< 354 Start mail input; end > with <CRLF>.<CRLF> > 3/19/02 12:16:22 PM : 499 Host unreachable: cta.net. Message > subject: ""Plain Text Test"". Rescheduling delivery for later. > > Notice that it seems to be going fine until it gets the 354 > message, then it sits for a little over a minute and seems to > time out. This particular test message was just a couple of > lines of plain text; so it shouldn't be a size issue. > > We've already restarted the IMS several times and the entire > Exchange server once. Judging by the oldest message in the > queue this problem seems to have started this weekend and no > unusual system maintenance or changes occurred over the > weekend. As far as I know we were able to send mail to/from > those domains just fine on Friday. > > Baffling. Any thoughts on what might be causing this and how > we can resolve it? > > -Ben- > Ben M. Schorr, MVP-Outlook, CNA, MCPx3 > Director of Information Services > Damon Key Leong Kupchak Hastert > http://www.hawaiilawyer.com <http://www.hawaiilawyer.com> > > > _________________________________________________________________ > List posting FAQ: http://www.swinc.com/resource/exch_faq.htm > Archives: http://www.swynk.com/sitesearch/search.asp > To unsubscribe: mailto:[EMAIL PROTECTED] > Exchange List admin: [EMAIL PROTECTED] > _________________________________________________________________ List posting FAQ: http://www.swinc.com/resource/exch_faq.htm Archives: http://www.swynk.com/sitesearch/search.asp To unsubscribe: mailto:[EMAIL PROTECTED] Exchange List admin: [EMAIL PROTECTED]
