IANA assigns port 5104 to tinymessage: TinyMessage.
Port 5104 is normally used over UDP; the checker tests TCP only, so a "filtered" result does not mean the UDP service is down.
Registry dates for this port: registered 2010-10-20.
sudo ss -ulnp 'sport = :5104'sudo lsof -nP -i :5104netstat -ano | findstr :5104Get-NetUDPEndpoint -LocalPort 5104nc -vzu -w 5 HOST 5104sudo ufw deny 5104/udpsudo iptables -A INPUT -p udp --dport 5104 -j DROPsudo nft add rule inet filter input udp dport 5104 dropNew-NetFirewallRule -DisplayName 'Block UDP 5104' -Direction Inbound -Protocol UDP -LocalPort 5104 -Action BlockAll port numbers · Open port checker
Assignment data: IANA port number registry (public domain), retrieved 2026-11-10.