636 LDAPS

LDAPS protects directory queries and authentication traffic with TLS from connection start.

Security Context

Port 636 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 636 <host>

UFW

sudo ufw allow 636/tcp

iptables

sudo iptables -A INPUT -p tcp --dport 636 -j ACCEPT