Hi Guys, We had a similar problem earlier this week with MSN.com SMTP server rejecting connections from our IMail Server (running 7.13 HF1). Another related thread here in the forum described not being able to send mail to a certain domain. Here's what happened and how we fixed it...
Problem: We noticed on a Monday that approx 1500 messages per day were piling up on our spool directory destined for msn.com email addresses. Our mail server would make 96 attempts to deliver each message (every 30 minutes for 48 hours). We could send mail to all other domains except this one. The log entries looked like this: 12:01 01:15 SMTP-(00000168) processing G:\IMAIL\spool\Q0fb5ee6.FWD 12:01 01:15 SMTP-(00000168) Trying msn.com (0) 12:01 01:15 SMTP-(00000168) Connect msn.com [207.46.181.13:25] (1) 12:01 01:15 SMTP-(00000168) 12:01 01:15 SMTP-(00000168) SMTP_DELIV_FAILED 12:01 01:15 SMTP-(00000168) >QUIT 12:01 01:15 SMTP-(00000168) 12:01 01:15 SMTP-(00000168) requeuing G:\IMAIL\spool\Q0fb5ee6.FWD R0 T14 12:01 01:15 SMTP-(00000168) finished G:\IMAIL\spool\Q0fb5ee6.FWD status=3 Not very descriptive. No error code or nothing. Checked all of these things: DNSReport.com said we looked good. Our DNS servers do allow recursive lookup for IPs in our network. We *could* Telnet to MSN's SMTP servers from the mail server machine. NIC settings, TCP/IP settings and MTU looked okay. It's a 3Com NIC that's been working fine for more than a year. Read every IMail KB article and Forum message that was remotely related - no luck. Finally in desperation I cracked open the system registry and started going through every setting under HKLM->Software->Ipswitch->IMAIL one-by-one and compared them to the registry of one of our customer's machines that's running IMail. Under each IP address key there are three values: (Default) Aliases Official Here's a picture from the IMail site that shows this: http://support.ipswitch.com/kb/IMAGES/1.gif The IP key for the main host for the entire mail server had the following entries/values: (Default) = mail.domain.com Aliases = domain.com (in hex, if I remember right) Official = mail.domain.com I cleared the entry mail.domain.com from the (Default) key and *poof* like magic! MSN.com started accepting our mail immediately (no reboot required). Apparently that one little reg key affected how (or if) MSN's SMTP servers determined our official hostname, did a reverse dns lookup or whatever other checks their SMTP servers are doing this week. Geez! Hotmail, Yahoo, AOL or any other SMTP server on the 'net didn't seem to have a problem with the previous registry settings and would allow us to connect with no problem. So, what's up with MSN anyway? Regards, Julie Silverman Microsoft Certified Systems Engineer, Network Geek ---------------------------------------------------------- Acme Internet http://www.acmeinternet.com voice: 952-928-8828 Microsoft Certified Partner ---------------------------------------------------------- ---------- Original Message ---------------------------------- From: Len Conrad <[EMAIL PROTECTED]> Reply-To: [EMAIL PROTECTED] Date: Thu, 05 Dec 2002 03:25:51 -0600 > >>If it was a DNS problem on our end, what would you guess it might be? > >commandline.net has no DNS errors, so Hotmail shouldn't be having any >problem validating you in DNS. > >>The TTL on our end? Meaning we have updates, albeit old data, still in >>our nameserver, which might be the reason that the IP's are not valid on >>the Hotmail side...? I am not sure. > >easy to fix, just stop and start your NS, which zeroes the cache of stale >or poisoned data. > >> I did a DNS report at >>http://www.dnsreport.com/ and got good scores for commandline.net, >>however, when I did it the first time it recommended that I set my SOA >>to expire after 14 days, do you think that could have anything to do >>with the Hotmail rejecetions? > >no. Hotmail isn't "rejecting" SMTP-lyyou via a policy. You have tcp/ip >"stack connect" failures trying to establish TCP/SMTP with ip's that your >DNS is telling Imail are the Hotmail MX hostname ip's. > >Can you have IMail use another recursive DNS? > >Can you take the list of ip's and from another machine telnet to port 25 of >each one and get an SMTP welcome banner from Hotmail MX? > >Len To Unsubscribe: http://www.ipswitch.com/support/mailing-lists.html List Archive: http://www.mail-archive.com/imail_forum%40list.ipswitch.com/ Knowledge Base/FAQ: http://www.ipswitch.com/support/IMail/
