2.1 KiB
2.1 KiB
Postfix SMTP Relay for RunCloud-Managed Servers
When a RunCloud-managed server (like wphost02) has stuck email in Postfix queue because port 25 is blocked, relay through mail.germainebrown.com:2525 with SASL auth and sender-domain rewriting.
Symptom
mailq shows 60+ messages deferred with (connect to ...:25: Connection timed out). The server tries to send directly to destination MX servers but port 25 is blocked.
Fix
# Configure relay
postconf -e "relayhost = mail.germainebrown.com:2525"
postconf -e "smtp_sasl_auth_enable = yes"
postconf -e "smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd"
postconf -e "smtp_sasl_security_options = noanonymous"
postconf -e "smtp_tls_security_level = encrypt"
postconf -e "myorigin = /etc/mailname"
# Auth credentials (use shonuff's SMTP account)
echo "mail.germainebrown.com:2525 shonuff@germainebrown.com:Catches.bullets1985" > /etc/postfix/sasl_passwd
chmod 600 /etc/postfix/sasl_passwd
postmap /etc/postfix/sasl_passwd
# Sender rewriting — MXroute requires real sender domain, not wphost02.local
echo "apextrackexperience.com" > /etc/mailname
echo "@wphost02 contact@apextrackexperience.com" > /etc/postfix/generic
echo "root@wphost02 contact@apextrackexperience.com" >> /etc/postfix/generic
postmap /etc/postfix/generic
postconf -e "smtp_generic_maps = hash:/etc/postfix/generic"
systemctl restart postfix
postqueue -f # flush the stuck queue
Verification
mailq says "Mail queue is empty". Logs show relay=mail.germainebrown.com[65.109.144.50]:2525 with status=sent.
Note
Old queued messages will get bounce notices (they were deferred too long). New emails flow through the relay cleanly. MXroute rejects 550 Envelope sender domain must be a fully qualified name if the sender is runcloud@wphost02 — the smtp_generic_maps rewrite fixes this.
Trigger Symptom Chain
- WP Mail SMTP on wphost02 configured for c1113726.sgvps.net:2525 (works for WP)
- PHP mail() falls back to Postfix, which does direct MX delivery on port 25
- Port 25 blocked → emails in deferred queue forever
- WPForms notifications and system emails pile up