← Back to all network ports
UDP
Vulnerable
137 NetBIOS Name Service
NetBIOS name resolution helps older Windows networks discover hosts and shared services.
Security Context
Port 137 is high-risk when broadly exposed. Treat it as an attack-surface decision, not just a connectivity setting, and confirm whether the listener truly needs to be reachable.
- !Legacy NetBIOS exposure leaks naming data useful for reconnaissance.
Nmap Check
Use a version probe first so you confirm whether the expected service is really what is listening on this port.
nmap -sU -p 137 <host>Firewall Commands
UFW
sudo ufw allow 137/udpiptables
sudo iptables -A INPUT -p udp --dport 137 -j ACCEPT