HTTPfy

Port 5350 (pcp-multicast)

IANA assigns port 5350 to pcp-multicast: Port Control Protocol Multicast.

Registered (user) port, 1024-49151 UDP

Port 5350 is normally used over UDP; the checker tests TCP only, so a "filtered" result does not mean the UDP service is down.

IANA assignment

Service nameProtoDescriptionAssigneeReference
pcp-multicast UDP Port Control Protocol Multicast IESG RFC 6887

Check what is listening on port 5350

Linux: UDP 5350
sudo ss -ulnp 'sport = :5350'
Linux / macOS: which process owns the port
sudo lsof -nP -i :5350
Windows (Command Prompt)
netstat -ano | findstr :5350
Windows (PowerShell)
Get-NetUDPEndpoint -LocalPort 5350

Test it from outside

UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 5350

Block port 5350 in the firewall

ufw
sudo ufw deny 5350/udp
iptables
sudo iptables -A INPUT -p udp --dport 5350 -j DROP
nftables
sudo nft add rule inet filter input udp dport 5350 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 5350' -Direction Inbound -Protocol UDP -LocalPort 5350 -Action Block

Related ports

5344xkotodrcp5349STUN / TURN over TLS5351pcp5352dns-llq

All port numbers · Open port checker
Assignment data: IANA port number registry (public domain), retrieved 2026-11-10.