NetBIOS and Samba Ports Revision as of Wednesday, 26 June 2024 at 10:57 UTC
| Service Name | Port | Protocol |
|---|---|---|
| Name Resolution Service | 137 | UDP |
| Datagram Services (browsing) | 138 | UDP |
| Session Service | 139 | TCP |
| SMB | 445 | TCP Input, UDP Output |
Observations
These are the contents of /etc/services:
netbios-ns 137/udp # NetBIOS Name Service
netbios-dgm 138/udp # NetBIOS Datagram Service
netbios-ssn 139/tcp # NetBIOS Session Service
microsoft-ds 445/tcp # Microsoft Directory Service
These are the ports that the Samba server listens on. A few things here:
- The first three are ports ports used by Windows to ‘find’ other
computers (a la “My Network”) - The last is for directory services
- UDP 137 and 138 are serviced by
nmbd - TCP 139 and 445 are serviced by
smbd