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Port 5104 (tinymessage)

IANA assigns port 5104 to tinymessage: TinyMessage.

Registered (user) port, 1024-49151 UDP

Port 5104 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
tinymessage UDP TinyMessage Josip Medved -

Registry dates for this port: registered 2010-10-20.

Check what is listening on port 5104

Linux: UDP 5104
sudo ss -ulnp 'sport = :5104'
Linux / macOS: which process owns the port
sudo lsof -nP -i :5104
Windows (Command Prompt)
netstat -ano | findstr :5104
Windows (PowerShell)
Get-NetUDPEndpoint -LocalPort 5104

Test it from outside

UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 5104

Block port 5104 in the firewall

ufw
sudo ufw deny 5104/udp
iptables
sudo iptables -A INPUT -p udp --dport 5104 -j DROP
nftables
sudo nft add rule inet filter input udp dport 5104 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 5104' -Direction Inbound -Protocol UDP -LocalPort 5104 -Action Block

Related ports

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