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Port 17222 (cpsp)

IANA assigns port 17222 to cpsp: Control Plane Synchronization Protocol (SPSP).

Registered (user) port, 1024-49151 UDP

Port 17222 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
cpsp UDP Control Plane Synchronization Protocol (SPSP) Randall Stewart 2 -

Registry dates for this port: registered 2011-11-10.

Check what is listening on port 17222

Linux: UDP 17222
sudo ss -ulnp 'sport = :17222'
Linux / macOS: which process owns the port
sudo lsof -nP -i :17222
Windows (Command Prompt)
netstat -ano | findstr :17222
Windows (PowerShell)
Get-NetUDPEndpoint -LocalPort 17222

Test it from outside

UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 17222

Block port 17222 in the firewall

ufw
sudo ufw deny 17222/udp
iptables
sudo iptables -A INPUT -p udp --dport 17222 -j DROP
nftables
sudo nft add rule inet filter input udp dport 17222 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 17222' -Direction Inbound -Protocol UDP -LocalPort 17222 -Action Block

Related ports

17220avtp17221avdecc17223isa100-gci17224trdp-pd

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