IANA's RTP AVT profile port, used as the default RTP port by some streaming tools; most VoIP systems allocate RTP from a range (for example 10000-20000).
Port 5004 is normally used over UDP; the checker tests TCP only, so a "filtered" result does not mean the UDP service is down.
IANA's RTP AVT profile port, used as the default RTP port by some streaming tools; most VoIP systems allocate RTP from a range (for example 10000-20000).
Expose only to trusted sources. Open the media range only towards your SIP provider or media servers.
sudo ss -ulnp 'sport = :5004'sudo lsof -nP -i :5004netstat -ano | findstr :5004Get-NetUDPEndpoint -LocalPort 5004nc -vzu -w 5 HOST 5004Replace 203.0.113.10 with the address or network you trust. With ufw, make sure the default incoming policy is deny.
sudo ufw allow from 203.0.113.10 to any port 5004 proto udpsudo iptables -A INPUT -p udp --dport 5004 -s 203.0.113.10 -j ACCEPT
sudo iptables -A INPUT -p udp --dport 5004 -j DROPsudo nft add rule inet filter input ip saddr 203.0.113.10 udp dport 5004 accept
sudo nft add rule inet filter input udp dport 5004 dropNew-NetFirewallRule -DisplayName 'UDP 5004 trusted' -Direction Inbound -Protocol UDP -LocalPort 5004 -RemoteAddress 203.0.113.10 -Action AllowAll port numbers · Open port checker
Assignment data: IANA port number registry (public domain), retrieved 2026-11-10.