Question about a different system. Pretty much every question of mine
is related to a different oddball case. Here I am helping a friend
out and they encountered this problem. I'll change the 3rd party
addresses so as not to annoy them but the data is otherwise
verbatim.
Sep 23 14:38:23 yuki postfix/smtp[21081]: CDC7E1438D:
to=<us...@comcast.net>, relay=mx2.comcast.net[68.87.20.5]:25, delay=2.7,
delays=0.08/0.06/2.5/0.05, dsn=4.1.0, status=deferred (host
mx2.comcast.net[68.87.20.5] said: 421 4.1.0 104.200.24.137 Throttled - try
again later. Please see
http://postmaster.comcast.net/smtp-error-codes.php#RL000001 (in reply to MAIL
FROM command))
Sep 23 14:38:23 yuki postfix/smtp[21081]: CDC7E1438D:
to=<us...@comcast.net>, relay=mx2.comcast.net[68.87.20.5]:25, delay=2.7,
delays=0.08/0.06/2.5/0.05, dsn=4.1.0, status=deferred (host
mx2.comcast.net[68.87.20.5] said: 421 4.1.0 104.200.24.137 Throttled - try
again later. Please see
http://postmaster.comcast.net/smtp-error-codes.php#RL000001 (in reply to MAIL
FROM command))
Sep 23 14:38:23 yuki postfix/smtp[21081]: CDC7E1438D:
to=<us...@comcast.net>, relay=mx2.comcast.net[68.87.20.5]:25, delay=2.7,
delays=0.08/0.06/2.5/0.05, dsn=4.1.0, status=deferred (host
mx2.comcast.net[68.87.20.5] said: 421 4.1.0 104.200.24.137 Throttled - try
again later. Please see
http://postmaster.comcast.net/smtp-error-codes.php#RL000001 (in reply to MAIL
FROM command))
This was one email sent to three recipients where all three just
happened to be at comcast.net and therefore they were grouped into one
SMTP transaction. All seemingly normal. But apparently Comcast has
decided to throttle based upon this.
My friend poked around and eventually deleted this message from the
queue and sent three messages one to each recipent and Comcast
accepted each of those three immediately. Therefore we conclude that
Comcast does not like multiple recipients in the same transaction.
Anyone think otherwise?
It seems that the way to add limits when sending to Comcast would be
to set up a transport map such as perhaps this. (And knowing that
Yerdle is a turtle.)
comcast.net yerdle:
Then add to the master.cf file.
smtp unix - - - - - smtp
yerdle unix - - - - - smtp
And add this to the main.cf file.
yerdle_destination_concurrency_limit = 1
yerdle_destination_rate_delay = 1s
yerdle_destination_recipient_limit = 1
That it would allow one connection at a time, with one recipient per
message at a time, and then a small delay between sending of messages.
Does that seem about right?
Bob
