sudo ss -ulnp | grep :170 Expected output:
[global] datagram port = 170 dgram port = 170 # older syntax Then restart Samba:
[global] disable netbios = yes smb ports = 445 Despite Microsoft’s deprecation of SMB1 and NetBIOS, countless embedded devices, medical imaging systems, and CNC machines still speak only NetBIOS over UDP ports 137/138 (or custom variants like port 170). For those administrators, SMBd remains a lifeline. Part 6: Troubleshooting Port 170 in SMBd 6.1 Verifying That SMBd/NMBd Is Listening Use netstat or ss : smbd 170
Introduction: The Whisper in the Machine In the sprawling ecosystem of network protocols, certain numbers become legendary: port 80 for the web, port 22 for secure shell, port 443 for encrypted traffic. But deep within the fabric of enterprise IT departments and legacy infrastructure, a quieter, often misunderstood port hums along: Port 170 .
| 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 ss -ulnp | grep :170 Expected output:
UNCONN 0 0 0.0.0.0:170 0.0.0.0:* users:(("nmbd",pid=1234,fd=7)) | Error | Likely Cause | Solution | |-------|--------------|----------| | bind failed on port 170: Address already in use | Another process (e.g., a second nmbd) owns the port | sudo lsof -i :170 to find and stop the conflict | | Clients cannot browse but can connect to shares | Datagram port mismatch or firewall blocking UDP 170 | Check iptables -L and client config | | smbd logs: Can't become connected master browser | Election packets lost on non-standard port | Ensure all potential master browsers use the same datagram port | 6.3 Firewall Rules for Port 170 If you intentionally use port 170, open it in your firewall:
sudo tcpdump -i eth0 udp port 170 Sample output: But deep within the fabric of enterprise IT
When paired with —the Linux, Unix, and BSD daemon that implements the Server Message Block (SMB) protocol—port 170 plays a critical role in NetBIOS datagram distribution. While modern Windows environments have shifted toward Direct SMB over TCP (port 445), countless industrial systems, older file servers, and hybrid networks still rely on the SMBd service’s ability to manage NetBIOS over TCP/IP. This article explores the technical depths of SMBd, the precise function of port 170, and why understanding this combination remains essential for system administrators today. Part 1: What is SMBd? The Heart of Samba 1.1 The Samba Suite SMBd is the core component of the Samba project, an open-source reimplementation of Microsoft’s SMB protocol suite. First released in 1992 by Andrew Tridgell, Samba allowed Unix-like systems to act as full-fledged Windows file and print servers.