Hi, I have a fedora23 system with postfix-3.0.4 configured as a mail relay and having some difficulty reaching some destinations due to apparent problems with too many concurrent connections.
I'm trying to solve the problem where this relay receives mail from one of the corporate servers where it is scanned on this relay server before being sent on to user's mailboxes. 279628D68138D 33026 Fri Jul 29 17:09:21 salest...@example.com (host mailstore1.secureserver.net[72.167.238.32] refused to talk to me: 421 p3plibsmtp01-06.prod.phx3.secureserver.net bizsmtp Connection refused, too many sessions from 66.104.132.100. Please lower the number of concurrent sessions. IB007 <http://x.co/rlbounce>) I've tried to configure destination concurrency, but I must not be doing it correctly. Can someone review my changes and let me know what I'm doing wrong? transport_maps = regexp:/etc/postfix/transport_limit default_destination_concurrency_limit = 10 turtle_initial_destination_concurrency = 1 turtle_destination_concurrency_limit = 1 turtle_destination_rate_delay = 4s turtle_destination_recipient_limit = 2 /etc/postfix/transport_limit: /secureserver\.net$/ turtle: I realize that by setting initial_destination_concurrency to 1 it's on a per-domain basis, which is what I believe I need. I've read the TUNING_README (a number of times over the years), but perhaps it was written before sites like secureserver.net have chosen to restrict inbound connections, not because of load, but instead for spam protection? Can someone make some recommendations on what the suggested/acceptible number of concurrent connections to sites like secureserver.net and others would be? Thanks, Alex
