465 SMTPS

SMTPS wraps SMTP in TLS from connection start for encrypted mail submission and relay paths.

Security Context

Port 465 is commonly expected on managed infrastructure, but it still needs scoped exposure, TLS where applicable, and service-specific hardening.

Use a version probe first so you confirm whether the expected service is really what is listening on this port.

nmap -sV -p 465 <host>

UFW

sudo ufw allow 465/tcp

iptables

sudo iptables -A INPUT -p tcp --dport 465 -j ACCEPT