I'm using MDaemon as out mail server and the last days I get an error "554 Message does not conform to standards" for emails sent from one of the machines. Any idea what may be causing it? Other machines work fine.
More info....this is the log file:
Mon 2008-10-20 16:11:37: Session 7831; child 1; thread 3908 Mon 2008-10-20 16:11:36: Accepting SMTP connection from [80.78.72.135 : 43579] Mon 2008-10-20 16:11:36: Performing PTR lookup (135.72.78.80.IN-ADDR.ARPA) Mon 2008-10-20 16:11:36: * Error: Name server reports domain name unknown Mon 2008-10-20 16:11:36: * No PTR records found Mon 2008-10-20 16:11:36: ---- End PTR results Mon 2008-10-20 16:11:36: --> 220 ikubinfo.com ESMTP MDaemon 9.5.2; Mon, 20 Oct 2008 16:11:36 +0200 Mon 2008-10-20 16:11:36: 250 ikubinfo.com Hello RS, pleased to meet you Mon 2008-10-20 16:11:36: Mon 2008-10-20 16:11:36: Performing IP lookup (ikubINFO.com) Mon 2008-10-20 16:11:36: * D=ikubINFO.com TTL=(633) A=[216.75.60.232] Mon 2008-10-20 16:11:36: * P=010 S=000 D=ikubINFO.com TTL=(708) MX=[mail.ikubinfo.com] Mon 2008-10-20 16:11:36: * D=ikubINFO.com TTL=(633) A=[216.75.60.232] Mon 2008-10-20 16:11:36: ---- End IP lookup results Mon 2008-10-20 16:11:36: Performing SPF lookup (ikubINFO.com / 80.78.72.135) Mon 2008-10-20 16:11:36: * ikubINFO.com 80.78.72.135; matched to SPF cache Mon 2008-10-20 16:11:36: * Result: pass Mon 2008-10-20 16:11:36: ---- End SPF results Mon 2008-10-20 16:11:36: --> 250 , Sender ok Mon 2008-10-20 16:11:36: Mon 2008-10-20 16:11:36: Performing DNS-BL lookup (80.78.72.135 - connecting IP) Mon 2008-10-20 16:11:36: * sbl-xbl.spamhaus.org - passed Mon 2008-10-20 16:11:36: * relays.ordb.org - failed Mon 2008-10-20 16:11:36: * bl.spamcop.net - passed Mon 2008-10-20 16:11:36: ---- End DNS-BL results Mon 2008-10-20 16:11:36: --> 250 , Recipient ok Mon 2008-10-20 16:11:37: 354 Enter mail, end with . Mon 2008-10-20 16:11:37: Message size: 389 bytes Mon 2008-10-20 16:11:37: --> 554 Message does not conform to standards Mon 2008-10-20 16:11:37: 221 See ya in cyberspace Mon 2008-10-20 16:11:37: SMTP session terminated (Bytes in/out: 491/319)
Answer
SMTP error 554 is one of the more vague error codes, but is typically caused by the receiving server seeing something in the From or To headers that it doesn't like. This can be caused by a spam trap identifying your machine as a relay, or as a machine not trusted to send mail from your domain.
We ran into this problem recently when adding a new server to our array, and we fixed it by making sure that we had the correct reverse DNS lookup set up.