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Port 40023 (k-patentssensor)

IANA assigns port 40023 to k-patentssensor: K-PatentsSensorInformation.

Registered (user) port, 1024-49151 UDP

Port 40023 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
k-patentssensor UDP K-PatentsSensorInformation Vaisala -

Registry dates for this port: registered 2015-12-02, last modified 2021-02-02.

Check what is listening on port 40023

Linux: UDP 40023
sudo ss -ulnp 'sport = :40023'
Linux / macOS: which process owns the port
sudo lsof -nP -i :40023
Windows (Command Prompt)
netstat -ano | findstr :40023
Windows (PowerShell)
Get-NetUDPEndpoint -LocalPort 40023

Test it from outside

UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 40023

Block port 40023 in the firewall

ufw
sudo ufw deny 40023/udp
iptables
sudo iptables -A INPUT -p udp --dport 40023 -j DROP
nftables
sudo nft add rule inet filter input udp dport 40023 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 40023' -Direction Inbound -Protocol UDP -LocalPort 40023 -Action Block

Related ports

39681turbonote-140000safetynetp40404sptx40841cscp

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