Port 3478 — STUN / TURN
Quick reference for TCP/UDP port 3478, used by STUN / TURN. Includes what the service does, security guidance and related ports.
What is port 3478?
NAT traversal for VoIP and WebRTC.
What port does STUN / TURN use?
STUN / TURN listens on port 3478 by default.
Is port 3478 open? How to check
Run one of these from your computer, replacing HOST with the IP address or domain you want to test.
nc -zv HOST 3478
Test-NetConnection HOST -Port 3478
nmap -p 3478 HOST
A refused or timed-out connection means the port is closed or filtered by a firewall.
Security guidance
Medium risk — open with care
Port 3478 (STUN / TURN) can safely face the internet if you keep the software up to date, restrict admin endpoints, and use TLS where possible. Audit who can reach it and watch your logs.
Related ports
Frequently asked
What is port 3478 used for?+
Port 3478 is the standard TCP/UDP port for STUN / TURN. NAT traversal for VoIP and WebRTC.
What port does STUN / TURN use?+
STUN / TURN listens on port 3478 by default.
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