On 5 August 2014 08:37, Laurie Brown laurie@brownowl.com wrote:
The above two errors appear to be contradictory!
That was my first thought.
However, there are two IP addresses given here for mx1.spamfiltering.com, and a quick DNS lookup confirms that there are indeed two A records. This would suggest that outbound email is being relayed via mx1.spamfiltering.com and that those two servers are perhaps configured differently (maybe same rules in different order, or different rules, or same rules but the 550 responses aren't set the same - from experience I don't trust the text that follows the 550 response to always bare any relationship to the real reason the email was rejected).
But copying the postfix config between machines may have left out the authentication settings, and would thus explain why it worked on one machine and fails on the next. There ought to be clues in /var/log/mail.log.
As an aside: unless things have changed, BT Internet mess around with SMTP traffic (and it can vary depending on which of their servers you hit). I seem to recall that attempts to use unencrypted SMTP on port 25 would (sometimes) get proxied to their servers, and that frequently they'd block any attempts to send mail from your own domain names in an attempt to block spam (?!*). I daresay some of these policies have changed since I last looked and they don't seem relevant here, but I would certainly suggest that postfix should be sending encrypted email to an authenticated mail relay if for no other reason that to bypass BT (there are lots of better reasons to be doing that anyway).
[?!*] "Blocking spam" didn't seem to be necessary on business accounts, but I'm not so bold as to suggest that this was really just about forcing anyone savvy enough to own their own domain to use a business account.
Mark