Port 389 — LDAP

TCP/UDP · Port 389 is used for the Lightweight Directory Access Protocol (LDAP) over TCP and UDP, allowing clients to query and manage directory services. This port is commonly used in enterprise networks for authentication and authorization purposes.

Port Number: 389
Service Name: LDAP
Protocol: TCP/UDP
Common Software: OpenLDAP, Active Directory

Security Notes

Review IANA registry for port 389 usage. Apply principle of least privilege - only open ports that are required.

FAQ

What is port 389 used for?

Port 389 is used for LDAP. Port 389 is used for the Lightweight Directory Access Protocol (LDAP) over TCP and UDP, allowing clients to query and manage directory services. This port is commonly used in enterprise networks for authentication and authorization purposes. Common software: OpenLDAP, Active Directory.

Is port 389 dangerous to leave open?

Review IANA registry for port 389 usage. Apply principle of least privilege - only open ports that are required.

How do I check if port 389 is open?

Use nmap: nmap -p 389 <target> or check locally: ss -tlnp | rg 389