Port 10809 (nbd)

IANA assigns port 10809 to nbd: Network Block Device.

Registered (user) port, 1024-49151 TCP

IANA assignment

Service nameProtoDescriptionAssigneeReference

nbd TCP Network Block Device Wouter Verhelst https://github.com/NetworkBlockDevice/nbd/blob/master/doc/proto.md

Registry dates for this port: registered 2010-08-02, last modified 2024-04-30.

Linux: is anything listening on TCP 10809?

sudo ss -tlnp 'sport = :10809'

Linux / macOS: which process owns the port

sudo lsof -nP -i :10809

Older Linux / BSD (net-tools)

sudo netstat -tlnp | grep ':10809 '

Windows (Command Prompt)

netstat -ano | findstr :10809

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 10809 -State Listen | Select LocalAddress,OwningProcess

From another machine

nc -vz -w 5 HOST 10809

From Windows

Test-NetConnection HOST -Port 10809

ufw

sudo ufw deny 10809/tcp

iptables

sudo iptables -A INPUT -p tcp --dport 10809 -j DROP

nftables

sudo nft add rule inet filter input tcp dport 10809 drop

Windows Firewall

New-NetFirewallRule -DisplayName 'Block TCP 10809' -Direction Inbound -Protocol TCP -LocalPort 10809 -Action Block

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