Port 17221 (avdecc)

IANA assigns port 17221 to avdecc: IEEE 1722.1 AVB Discovery, Enumeration, Connection management, and Control.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference

avdecc TCP IEEE 1722.1 AVB Discovery, Enumeration, Connection management, and Control IEEE 1722 1 -

avdecc UDP IEEE 1722.1 AVB Discovery, Enumeration, Connection management, and Control IEEE 1722 1 -

Registry dates for this port: registered 2011-11-01.

Linux: is anything listening on TCP 17221?

sudo ss -tlnp 'sport = :17221'

Linux: UDP 17221

sudo ss -ulnp 'sport = :17221'

Linux / macOS: which process owns the port

sudo lsof -nP -i :17221

Older Linux / BSD (net-tools)

sudo netstat -tlnp | grep ':17221 '

Windows (Command Prompt)

netstat -ano | findstr :17221

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 17221 -State Listen | Select LocalAddress,OwningProcess

From another machine

nc -vz -w 5 HOST 17221

From Windows

Test-NetConnection HOST -Port 17221

UDP probe (no reply does not prove it is closed)

nc -vzu -w 5 HOST 17221

ufw

sudo ufw deny 17221/tcp

iptables

sudo iptables -A INPUT -p tcp --dport 17221 -j DROP

nftables

sudo nft add rule inet filter input tcp dport 17221 drop

Windows Firewall

New-NetFirewallRule -DisplayName 'Block TCP 17221' -Direction Inbound -Protocol TCP -LocalPort 17221 -Action Block

ufw

sudo ufw deny 17221/udp

iptables

sudo iptables -A INPUT -p udp --dport 17221 -j DROP

nftables

sudo nft add rule inet filter input udp dport 17221 drop

Windows Firewall

New-NetFirewallRule -DisplayName 'Block UDP 17221' -Direction Inbound -Protocol UDP -LocalPort 17221 -Action Block

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Assignment data: IANA port number registry (public domain), retrieved 2026-11-10.