SMB Protocol Ports

To provide file and print sharing services within a network, SMB uses a number of ports. The following are all known SMB v2/v3 ports:

TCP 445 — SMB over transmission control protocol (TCP) without the need for a network basic input/output system (NetBIOS)

UDP 137 — SMB over user datagram protocol (UDP or Name Services) UDP 138 — SMB over UDP (datagram)

TCP 139 — SMB over TCP (session service)