Qmail Relay Server Integration via smtproutes

Qmail is a classic MTA known for its security-focused design. Due to its modular structure, relay configuration is managed through the smtproutes file.

Relay via smtproutes

In /var/qmail/control/smtproutes:

# Route all outbound to Pitbull relay
:relay.pitbull.com.tr:587

# Per-domain (optional)
example.com:relay.pitbull.com.tr:587

TLS and AUTH

Qmail's default installation lacks SMTP AUTH and TLS support. The netqmail + TLS patch must be applied. After patching, /var/qmail/control/smtproutes can relay over TLS.

Inbound MX Gateway

Point DNS MX records to the Pitbull gateway to pass inbound traffic through centralized filtering. Clean messages are delivered to your Qmail server.

Conclusion

Qmail's security architecture is complemented by the Pitbull relay layer, providing both inbound and outbound protection.