Port 636 — LDAPS
Quick reference for TCP/UDP port 636, used by LDAPS. Includes what the service does, security guidance and related ports.
What is port 636?
LDAP over TLS.
What port does LDAPS use?
LDAPS listens on port 636 by default.
Is port 636 open? How to check
Run one of these from your computer, replacing HOST with the IP address or domain you want to test.
nc -zv HOST 636
Test-NetConnection HOST -Port 636
nmap -p 636 HOST
A refused or timed-out connection means the port is closed or filtered by a firewall.
Security guidance
Medium risk — open with care
Port 636 (LDAPS) can safely face the internet if you keep the software up to date, restrict admin endpoints, and use TLS where possible. Audit who can reach it and watch your logs.
Related ports
Frequently asked
What is port 636 used for?+
Port 636 is the standard TCP/UDP port for LDAPS. LDAP over TLS.
What port does LDAPS use?+
LDAPS listens on port 636 by default.
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