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Port 11430 (lsdp)

IANA assigns port 11430 to lsdp: Lenbrook Service Discovery Protocol.

Registered (user) port, 1024-49151 UDP

Port 11430 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
lsdp UDP Lenbrook Service Discovery Protocol Lenbrook Industries Limited -

Registry dates for this port: registered 2014-03-27.

Check what is listening on port 11430

Linux: UDP 11430
sudo ss -ulnp 'sport = :11430'
Linux / macOS: which process owns the port
sudo lsof -nP -i :11430
Windows (Command Prompt)
netstat -ano | findstr :11430
Windows (PowerShell)
Get-NetUDPEndpoint -LocalPort 11430

Test it from outside

UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 11430

Block port 11430 in the firewall

ufw
sudo ufw deny 11430/udp
iptables
sudo iptables -A INPUT -p udp --dport 11430 -j DROP
nftables
sudo nft add rule inet filter input udp dport 11430 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 11430' -Direction Inbound -Protocol UDP -LocalPort 11430 -Action Block

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Assignment data: IANA port number registry (public domain), retrieved 2026-11-10.