Have circumvented the problem by adding "smtpd_tls_exclude_ciphers = RC4-MD5" to my /etc/postfix/main.cf.
Google is now using RC4-SHA instead, and I've experienced no further problems so far. Obviously this may not be a postfix bug (it seems openssl-related issues can even be cause by compiler optimization or other issues and it seems likely in any case that the bug is in the openssl library that postfix is using) but I am more than willing to help diagnose it, whatever package it belongs in. It should be 100% reproducible if I stop the cipher exclusion unless google changes something on their end. -- You received this bug notification because you are a member of Ubuntu Server Team, which is subscribed to postfix in Ubuntu. https://bugs.launchpad.net/bugs/1001040 Title: "TLS library problem" drops incoming mail when sender uses RC4-MD5 cipher To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/postfix/+bug/1001040/+subscriptions -- Ubuntu-server-bugs mailing list Ubuntu-server-bugs@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-server-bugs