On Tue, Apr 19, 2016 at 12:49:01PM -0400, Steven Peterson wrote: > In general this works > well, but with some ISPs, when deferring our e-mail, the only entry in the > postfix logs is under the 'error' process. For most ISPs, the smtp process > has the results of the conversations. Which process logs the 'deferral' > notice is important because 1) we need the normalized format output by the > smtp process; and 2) we need the custom log name that accompanies the smtp > process.
This is not especially ISP-specific. Mail is deferred by the "error" delivery agent (via the "retry" transport) when the destination queue is "throttled" after too many connection-related failures. While the destination is throttled, any already accumulated messages in the active queue and newly arriving messages are efficiently drained into the deferred queue. You'll see this when the remote server consistently returns 4XX/5XX at banner or EHLO or disconnects with a 421/521 mid transaction. > Apr 19 01:35:45 mail4 br-shared/error[27280]: 1BBB6CE7605: to=< > recipi...@comcast.net>, relay=none, delay=0.05, delays=0.05/0/0/0, > dsn=4.0.0, status=deferred (delivery temporarily suspended: host > mx2.comcast.net[68.87.20.5] refused to talk to me: 421 > resimta-ch2-16v.sys.comcast.net comcast 130.94.24.84 Throttled - try again > later. k5Cs1s00N1ors0201 Please see > http://postmaster.comcast.net/smtp-error-codes.php#RL000002) As promised, comcast was turning away your connections. Postfix complies. The "refused to talk to me: 421" indicates a reject at banner or EHLO. > -- /etc/postfix-br/master.cf -- > acct_client1 unix - - n - - smtp > -o syslog_name=br-client1 > -o smtp_bind_address=185.94.24.84 > -o smtp_helo_name=news.client1.org The SMTP delivery agent is not invoked when the destination is throttled. -- Viktor.
