Port 3478: STUN / TURN
NAT traversal for WebRTC calls and video. Needed for TURN servers. Misconfigured TURN servers can be used as open relays.
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Port Lookup
Port 3478 at a glance
Port3478
ProtocolTCP/UDP
ServiceSTUN / TURN
Open to the Internet?Yes, if you run this service publicly
See What Is Listeningss -lntup | grep ':3478 '
Test From Outsidenc -zv your-server 3478
Block with UFWufw deny 3478/tcp; ufw deny 3478/udp
Block with nftablesnft add rule inet filter input meta l4proto { tcp, udp } th dport 3478 drop
STUN / TURN uses TCP/UDP port 3478. NAT traversal for WebRTC calls and video.
Needed for TURN servers. Misconfigured TURN servers can be used as open relays.
Open port 3478 only on servers that run STUN / TURN, and keep the software patched: public services are scanned within minutes of going online.
Other Ports
20 FTP Data21 FTP22 SSH23 Telnet25 SMTP53 DNS67 DHCP Server80 HTTP110 POP3123 NTP143 IMAP161 SNMP389 LDAP443 HTTPS445 SMB465 SMTPS514 Syslog587 Mail Submission853 DNS over TLS993 IMAPS995 POP3S1194 OpenVPN1433 Microsoft SQL Server1900 SSDP / UPnP2049 NFS2083 cPanel (SSL)2087 WHM (SSL)3306 MySQL / MariaDB3389 RDP3478 STUN / TURN5060 SIP5432 PostgreSQL5900 VNC6379 Redis8006 Proxmox VE8080 HTTP Alternate8443 HTTPS Alternate11211 Memcached25565 Minecraft27017 MongoDB51820 WireGuard
Questions
What is port 3478 used for?
STUN / TURN. NAT traversal for WebRTC calls and video.
Is it safe to open port 3478?
Yes, if you run this service publicly. Needed for TURN servers. Misconfigured TURN servers can be used as open relays.
How do I check if port 3478 is open?
On the server, ss -lntup | grep ':3478 ' shows what is listening. From another machine, nc -zv your-server 3478 shows whether the firewall lets it through.
How do I block port 3478?
With UFW: ufw deny 3478/tcp and ufw deny 3478/udp. With nftables, add a drop rule for dport 3478 in your input chain.
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