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Port 21337 (xahaud)

IANA assigns port 21337 to xahaud: Xahau P2P network protocol.

Registered (user) port, 1024-49151 TCP

IANA assignment

Service nameProtoDescriptionAssigneeReference
xahaud TCP Xahau P2P network protocol INFTF MTU https://xahau.network

Registry dates for this port: registered 2025-10-16.

Check what is listening on port 21337

Linux: is anything listening on TCP 21337?
sudo ss -tlnp 'sport = :21337'
Linux / macOS: which process owns the port
sudo lsof -nP -i :21337
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':21337 '
Windows (Command Prompt)
netstat -ano | findstr :21337
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 21337 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 21337
From Windows
Test-NetConnection HOST -Port 21337

Block port 21337 in the firewall

ufw
sudo ufw deny 21337/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 21337 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 21337 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 21337' -Direction Inbound -Protocol TCP -LocalPort 21337 -Action Block

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21213cohesity-agent21221aigairserver21553rdm-tfs21554dfserver

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