I'm running Postfix on Debian as an MX for a small LAN and trying to get SMTPS working with mobile.charter.net over port 587. I followed a few links off google for setting this up along with a post on serverfault with a similar question. I've tried sending a few emails but getting this error about "initial server greeting" in the mail log:
Nov 17 03:39:14 edgemx postfix/smtp: 9B39AA4: to=<firstname.lastname@example.org>, relay=mobile.charter.net[184.108.40.206]:587, delay=473, delays=173/0.03/300/0, dsn=4.4.2, status=deferred (conversation with mobile.charter.net[220.127.116.11] timed out while receiving the initial server greeting)
I ran a tcpdump on port 587 while sending and I don't see the certificate transfer happening between Postfix and Charter. There's like three SYN packets and that's it. If I use openssl in client mode to connect, the tcpdump traffic is much different and I can see a cert transfer happen.
openssl s_client -connect mobile.charter.net:587
Anyone know what's up? What is openssl doing that Postfix isnt? relevant SASL/SSL edits in main.cf are below.
smtp_sasl_auth_enable = yes smtp_sasl_password_maps = hash:/etc/postfix/relayhost_passwd smtp_sasl_security_options = noanonymous smtp_use_tls = yes smtp_tls_security_level = encrypt relayhost = [mobile.charter.net]:587 smtp_tls_mandatory_ciphers = high
relayhost_passwd file (postmap'd already)