Thanks Scott. I figured Symantec were at fault here, since we had no issues with this before. Perhaps they've fixed this with v7 of their software. I know their smtp proxy received some attention.
Josh ----- Original Message ----- From: "R. Scott Perry" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Thursday, August 15, 2002 4:03 PM Subject: Re: [IMail Forum] mx rollover issue > > >umoncton.ca MX preference = 20, mail exchanger = cujam.ci.umoncton.ca > >umoncton.ca MX preference = 10, mail exchanger = altair.ci.umoncton.ca > > > >cujam.ci.umoncton.ca internet address = 139.103.2.10 > >altair.ci.umoncton.ca internet address = 139.103.2.3 > > > >Our logs show attempts to connect to 139.103.2.3 only. Interestingly, I > >cannot telnet to 139.103.2.3, but I can to 139.103.2.10. > > Here, I can not connect to 139.103.2.3. I'm guessing umoncton.ca is one of > these extremely poorly designed domains that intentionally has a wasteful > MX record that goes nowhere (read: they have clueless admins). > > >Symantec's knowledgebase has an entry on mx rollover issues, and blames the > >smtp server. It states: "Some mail servers will not roll over to the second > >MX record because they do not properly interpret the 421 SMTP error message > >returned by the firewall. The mail server believes it has already made a > >successful connection with the remote mail server when it has only > >communicated with the Raptor Firewall's SMTP proxy. The SMTP server will not > >even try the second MX record." > > The problem here is with Symantec. They are translating umoncton.ca's "You > aren't allowed to connect here" (which IMail properly handles as a "try the > next MX record" response) into "The server is shutting down -- please try > again before contacting the next MX record). > > In this case, Symantec is definitely in the wrong. See > http://www.mail-archive.com/[email protected]/msg48276.html for > more details on this Symantec problem (from February -- 6 months later, > they still haven't fixed their problem). > > 421 specifically indicates a *temporary* error per the RFCs -- Symantec is > returning this when there is an error that is permanent. > > -Scott > --- > Declude: Anti-virus, Anti-spam and Anti-hijacking solutions for > IMail. http://www.declude.com > > --- > [This E-mail was scanned for viruses by Declude Virus (http://www.declude.com)] > > > 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/ > --- > [This E-mail scanned for viruses by Declude Virus] > > --- [This E-mail scanned for viruses by Declude Virus] 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/
