I've had a long-running problem with messages sent from comcast.net addresses bouncing back to the sender. I thought this could be due to the postscreen deep protocol checks I use with postfix-2.11_pre*, but I added the following to main.cf on August 15th and yesterday I received a message from someone with a comcast.net address who says their email bounced:
postscreen_dnsbl_sites = zen.spamhaus.org list.dnswl.org*-1 postscreen_dnsbl_whitelist_threshold = -1 I grep'ed my mail logs for his address and found only this: Aug 18 * 450 4.3.2 Service currently unavailable I've searched my inbox and trash and I do not see his message so I don't think Comcast retried. I do have one of these bounced messages that was forwarded to me about 9 weeks ago but there is no indication of what the problem was. Besides headers, the message includes no more information than this: SUBJECT: Delivery status notification This is an automatically generated Delivery Status Notification. Delivery to the following recipients was aborted after 7 second(s): mas...@masked.com - Grant
