Port 138 — NetBIOS-DGM

UDP · Port 138 is used for NetBIOS datagram services, which facilitate communication between devices on a local network. This service is relevant to security as it can be exploited by attackers to spread malware or conduct reconnaissance attacks.

Port Number: 138
Service Name: NetBIOS-DGM
Protocol: UDP
Common Software: Samba, Windows

Security Notes

Review IANA registry for port 138 usage. Apply principle of least privilege - only open ports that are required.

FAQ

What is port 138 used for?

Port 138 is used for NetBIOS-DGM. Port 138 is used for NetBIOS datagram services, which facilitate communication between devices on a local network. This service is relevant to security as it can be exploited by attackers to spread malware or conduct reconnaissance attacks. Common software: Samba, Windows.

Is port 138 dangerous to leave open?

Review IANA registry for port 138 usage. Apply principle of least privilege - only open ports that are required.

How do I check if port 138 is open?

Use nmap: nmap -p 138 <target> or check locally: ss -tlnp | rg 138