Date: 2007dec14 OS: Linux Product: Postfix Q. Postfix: make Postfix support TLS A. This is a nice thing to enable since it'll encrypt the mail it exchanges with other SMTP agents that support TLS. No need to use PGP, etc. With RedHat/Fedora/CentOS its pretty easy. Make a self-signed certificate like this:

cd /etc/pki/tls/certs make postfix.pem

Add these options to /etc/postfix/main.cf:

smtpd_tls_auth_only = no smtp_use_tls = yes smtpd_use_tls = yes smtp_tls_note_starttls_offer = yes smtpd_tls_key_file = /etc/pki/tls/certs/postfix.pem smtpd_tls_cert_file = /etc/pki/tls/certs/postfix.pem smtpd_tls_loglevel = 1 smtpd_tls_received_header = yes smtpd_tls_session_cache_timeout = 3600s tls_random_source = dev:/dev/urandom

Restart Postfix:

systemctl restart postfix

Use of TLS will be noted in your mail headers and the Postfix log. For example:

Nov 24 16:15:28 www postfix/smtpd[9410]: connect from mail.example.com[1.2.3.3] Nov 24 16:15:28 www postfix/smtpd[9410]: setting up TLS connection from mail.example.com[1.2.3.4] Nov 24 16:15:28 www postfix/smtpd[9410]: Anonymous TLS connection established from mail.example.com[1.2.3.4]: TLSv1 with cipher ADH-AES256-SHA (256/256 bits)