| Service | Port | Protocol | Purpose | |---------|------|----------|---------| | Name Service | 137 | UDP/TCP | Register/resolve NetBIOS names | | Datagram Service | | UDP | Connectionless broadcast/multicast messages | | Session Service | 139 | TCP | Connection-oriented file/print sharing |
sudo systemctl restart nmbd sudo systemctl restart smbd After this change, nmbd will send and receive datagram packets on UDP 170 instead of UDP 138. Clients must be configured to match, making this a purely internal or testing configuration. A tcpdump capture on a Samba server using port 170 would show: smbd 170
Wait—, not 170. So where does 170 come from? 2.2 The Mystery of Port 170 Port 170 is not a standard IANA-assigned NetBIOS port. In fact, the IANA registry lists port 170 as “Network PostScript” (a relic of printer sharing). However, within the context of SMBd and legacy Windows networking , port 170 appears as a historical or vendor-specific extension for certain NetBIOS datagram variations. | Service | Port | Protocol | Purpose
sudo tcpdump -i eth0 udp port 170 Sample output: So where does 170 come from
[global] datagram port = 170 dgram port = 170 # older syntax Then restart Samba:
The SMBd daemon, through its unassuming configuration options, embodies the philosophy of Samba: . Whether on standard UDP 138 or on an obscure port like 170, the daemon faithfully translates between the messy reality of legacy Windows networking and the clean world of POSIX systems.