Diagnostic-Code: SMTP; 571 Denied by policy
I've found that message this morning. reported by a user from one of the mail servers I manage. Two of those mail servers are almost identical, same Operating System (FreeBSD), same configuration (Sendmail + Cyrus + SASL + OpenLDAP). Each server is located in a completely different ip range and a user from one of the servers, let's call it ServerP reported a returning mail error like:
From: Mail Delivery Subsystem <MAILER-DAEMON@ServerP> To: <user@ServerP_domain.com> Subject: Returned mail: see transcript for details Date: Fri, 9 May 2008 13:41:16 +0200 (CEST) The original message was received at Fri, 9 May 2008 13:41:12 +0200 (CEST) from whatever.whatever.com [213.60.82.227] ----- The following addresses had permanent fatal errors ----- <destination_user@ISM.seg-social.es> (reason: 571 Denied by policy ) ----- Transcript of session follows ----- ... while talking to smtp.seg-social.es.: >>> MAIL From:<user@ServerP_domain.com> SIZE=850 <<< 571 Denied by policy 554 5.0.0 Service unavailable [message/delivery-status (320B)] Reporting-MTA: dns; dns.ServerP_domain.com Received-From-MTA: DNS; whatever.whatever.com Arrival-Date: Fri, 9 May 2008 13:41:12 +0200 (CEST) Final-Recipient: RFC822; destination_user@ISM.seg-social.es Action: failed Status: 5.0.0 Diagnostic-Code: SMTP; 571 Denied by policy Last-Attempt-Date: Fri, 9 May 2008 13:41:16 +0200 (CEST)
(of course, I've replaced real data with dummy information, but the destination server is smtp.seg-social.es for real)
At first I thought it could be a destintation server problem (or that's what 554 5.0.0 Service unavailable means to me), but then I tried to send an email to the same destination address from the other server, let's call it ServerC, and that one got through, reaching the destination address mailbox.
Well, that pointed me back to the message:
571 Denied by policy
Denied by policy, what could that mean? it seems like some kind of local, server-side filtering for me, but I'm not sure. Could it be that the ip address of ServerP is in some kind of local blacklist?, don't know really.
Searching through Google, the only releveant information pointed me to a windows 2003 mail server with a bad DNS configuration, but hey, that smtp.seg-social.es is the mail server for a spanish government institution... it couldn't be that the server is so badly configured...
Any ideas? Someone suffered that problem before?