// REFERENCE
Port 139 (NetBIOS Session / SMB)
Protocol: TCP
Service: SMB over NetBIOS
High risk
SMB over NetBIOS: file and printer sharing on legacy Windows. Modern SMB uses 445. Exposed it's a surface for worms and hash theft; block it at the perimeter.
Related tools
Work with this in:
Related
20
Port 20 (FTP-DATA) 21
Port 21 (FTP) 69
Port 69 (TFTP) 445
Port 445 (SMB) 873
Port 873 (rsync) 989
Port 989 (FTPS data)
Port 20 (FTP-DATA) 21
Port 21 (FTP) 69
Port 69 (TFTP) 445
Port 445 (SMB) 873
Port 873 (rsync) 989
Port 989 (FTPS data)
Assignments per the IANA port registry. Educational content.