@CCAntiSpam you have helped us with an issue in the past, I wonder if you're able to help again. Our customers are experiencing problems receiving emails from our mail servers to comcast.net accounts right now. Our logs are flooded with deferral messages like:
Dec 2 15:37:24 *** postfix/error: 7035761EDA: to=<***@comcast.net>, relay=none, delay=0.06, delays=0.05/0/0/0, dsn=4.4.2, status=deferred (delivery temporarily suspended: lost connection with mx2.comcast.net[18.104.22.168] while sending MAIL FROM)
It started this morning and is happening across all of our servers. We maintain an excellent sender score reputation, sanitize our mail well, aren't on any blacklists, so I'm not sure why we're getting all the deferrals. Seems to only be happening with the comast.net domain.
@emillerccb You didn't provide any IPs to inspect, though it looks more like a session timeout, not a policy violation
Our smtp timeout is set orders of magnitutde above the amount of delay on all of these messages (< 1s). Is that what you're referring to by session timeout?
Also, upon further inspection, the full message was:
(delivery temporarily suspended: lost connection with mx1.comcast.net[22.214.171.124] while sending end of data -- message may be sent more than once)
So far this doesn't seem to be happening today. It looks like the issue started resolving itself around 4pm ET yesterday.