UDP Port 138 – netbios-dgm

About UDP Port 138

Port 138 is registered with the Internet Assigned Numbers Authority (IANA) for netbios-dgm. The IANA description reads: ‘NETBIOS Datagram Service’. This port appears in 2 IDS rules and does not have notable malware activity indicators in our data.

IDS Rule References

2 IDS / security rules reference UDP port 138. Presence in IDS rules does not mean traffic on this port is malicious. These are patterns security tools monitor.

Rule categories (top 2): attempted-recon (1), attempted-admin (1).

Sample rule descriptions for UDP port 138:

• OS-WINDOWS DCERPC NCADG-IP-UDP lsass DsRolerUpgradeDownlevelServer overflow attempt
• ET SCAN Nessus Netbios Scanning

Data Sources

This information is compiled from: IANA Service Name and Transport Protocol Port Number Registry, Emerging Threats Open Ruleset (BSD 2-Clause / GPLv2 per SID range), and Snort Community Rules (GPLv2).