Port 41121 (tentacle)

IANA assigns port 41121 to tentacle: Tentacle Server.

Registered (user) port, 1024-49151 TCP

IANA assignment

Service nameProtoDescriptionAssigneeReference

tentacle TCP Tentacle Server Sancho Lerena -

Registry dates for this port: registered 2009-06-02.

Linux: is anything listening on TCP 41121?

sudo ss -tlnp 'sport = :41121'

Linux / macOS: which process owns the port

sudo lsof -nP -i :41121

Older Linux / BSD (net-tools)

sudo netstat -tlnp | grep ':41121 '

Windows (Command Prompt)

netstat -ano | findstr :41121

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 41121 -State Listen | Select LocalAddress,OwningProcess

From another machine

nc -vz -w 5 HOST 41121

From Windows

Test-NetConnection HOST -Port 41121

ufw

sudo ufw deny 41121/tcp

iptables

sudo iptables -A INPUT -p tcp --dport 41121 -j DROP

nftables

sudo nft add rule inet filter input tcp dport 41121 drop

Windows Firewall

New-NetFirewallRule -DisplayName 'Block TCP 41121' -Direction Inbound -Protocol TCP -LocalPort 41121 -Action Block

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