If a host answers and rejects the message, the message won't be rejected to another server. For example, a customer of mine had three ISP-managed MX recoreds, two of which pointed to a service provider that no longer hosted its domain. Had its primary mail server died, sending SMTP servers would try the bad alternates, which would bounce the messages. Without the two bad alternate MX records, the sending SMTP servers would retry for a while.
Maybe what's happening in your case is that one of the two SMTP servers is misconfigured or something. Try doing a telnet session to port 25 on each to see if you can get any clues. Ed Crowley MCSE+I MVP Technical Consultant hp Services "There are seldom good technological solutions to behavioral problems." -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of Kevin Cobb Sent: Wednesday, October 02, 2002 1:07 PM To: Exchange Discussions Subject: RE: win2k sp2 smtp server error 5.0.0 I seem to be having the same issue with Exchange not mailing some domains, while mailing others just fine. (I also seen the same from time to time with Hotmail). What I've tracked down and believe to be happening is when a primary mx record is not answering, our exchange 2000 server is not attempting to mail to the secondary server. I'm seeing this on two other exchange 2000 servers as well. I fired up the older lotus notes server and watched the logs as it attempted mailing to the "bad domain". The logs show that the initial mx record was attempted and failed, but then connected to the secondary and mail is transferred. Unfortuantely I cannot find any logs of this nature in exchange to show the process, but every domain in the "retry queue" with "Connection Dropped by the Remote Host" has a primary MX record that is not responding. Anyone have any clues on what might be going on on the Exchange box there? It's set up behind an ISA server. Has local and remote DNS lookup. Can resolve NSLOOKUPs from the exchange server. It just doesn't seem to want to attempt a secondary MX record if the primary fails. Any ideas would be greatly appreciated, and would save hairs on my head! Kevin Cobb Network Manager (703) 449-7600 > Updated -=20 > > I think I might have found the problem: > > http://support.microsoft.com/default.aspx?scid=3Dkb;en-us;Q240832 > > but if I set it to use HELO, I don't get the option for it to use > EHLO, so I would lose the ability to send out as ESMTP?? > > > > Rob Ellis=20 > Network Manager=20 > Profectus IT=20 > Tel 023 9224 7960=20 > Mob 07974 111867 > > > -----Original Message----- > From: Rob Ellis=20 > Sent: 26 September 2002 15:37 > To: Exchange Discussions > Subject: win2k sp2 smtp server error 5.0.0 > > Using a Win2K sp2 box in our DMZ running the MS smtp server, as a > relay for our E2K server. All incoming traffic flows fine, but we are > getting a number of NDRs such as: > > The e-mail system was unable to deliver the message, but did not > report a specific reason. Check the address and try again. If it > still fails, contact your system administrator. > > <mail.profectus.co.uk #5.0.0 smtp;500 Syntax error, command > unrecognized> > > this is happening for a variety of domain names, including hotmail.com > (which I'm not that worried about, but some of the domains are > actually 'proper' domains.) > > Could it be that the IP that our server sits on has been blacklisted > by certain ISPs? > > > > Rob Ellis=20 > Network Manager=20 > Profectus IT=20 > Tel 023 9224 7960=20 > Mob 07974 111867 > > > > _________________________________________________________________ > 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]
