Port 3478: STUN/TURN

Port 3478 is STUN and TURN, the protocols that help two devices behind NAT establish a direct connection for real-time voice, video, or WebRTC data. When a direct connection cannot be made, a TURN server on this port relays the media instead.

TCP/UDPProxy & tunnelingUnencrypted by defaultIANA assigned
Port number3478
ServiceSTUN/TURN (NAT traversal for WebRTC)
ProtocolTCP/UDP
CategoryProxy & tunneling
Default encryptionNo
Security note. Port 3478 is not encrypted by default. Restrict it to trusted networks, or use an encrypted alternative where one exists, to avoid exposing credentials and data in transit.

Frequently asked questions

What is port 3478 used for?

Port 3478 is STUN and TURN, the protocols that help two devices behind NAT establish a direct connection for real-time voice, video, or WebRTC data. When a direct connection cannot be made, a TURN server on this port relays the media instead.

Is port 3478 TCP or UDP?

Port 3478 (STUN/TURN) uses TCP/UDP.

Is port 3478 secure?

Port 3478 is not encrypted by default. Where possible, use an encrypted alternative or tunnel it over TLS or a VPN.

Should I open port 3478 on my firewall?

Only if you specifically need STUN/TURN. Expose it to the smallest set of trusted sources, and never open database or Windows-service ports to the whole internet.