The term, I believe, is black-hole router. ----- Original Message ----- From: "Ben Schorr" <[EMAIL PROTECTED]> To: "Exchange Discussions" <[EMAIL PROTECTED]> Sent: Tuesday, March 19, 2002 9:54 PM Subject: RE: Some "Hosts Unreachable" - Follow-up
> 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] > _________________________________________________________________ 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]
