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Port 4804 (aja-ntv4-disc)

IANA assigns port 4804 to aja-ntv4-disc: AJA ntv4 Video System Discovery.

Registered (user) port, 1024-49151 UDP

Port 4804 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
aja-ntv4-disc UDP AJA ntv4 Video System Discovery Mike Bernadett -

Registry dates for this port: registered 2010-06-03.

Check what is listening on port 4804

Linux: UDP 4804
sudo ss -ulnp 'sport = :4804'
Linux / macOS: which process owns the port
sudo lsof -nP -i :4804
Windows (Command Prompt)
netstat -ano | findstr :4804
Windows (PowerShell)
Get-NetUDPEndpoint -LocalPort 4804

Test it from outside

UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 4804

Block port 4804 in the firewall

ufw
sudo ufw deny 4804/udp
iptables
sudo iptables -A INPUT -p udp --dport 4804 -j DROP
nftables
sudo nft add rule inet filter input udp dport 4804 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 4804' -Direction Inbound -Protocol UDP -LocalPort 4804 -Action Block

Related ports

4802ilss4803notateit, notateit-disc4827htcp4837varadero-0

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