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Port 4421 (scaleft)

IANA assigns port 4421 to scaleft: Multi-Platform Remote Management for Cloud Infrastructure.

Registered (user) port, 1024-49151 TCP

IANA assignment

Service nameProtoDescriptionAssigneeReference
scaleft TCP Multi-Platform Remote Management for Cloud Infrastructure ScaleFT Inc -

Registry dates for this port: registered 2016-04-07.

Check what is listening on port 4421

Linux: is anything listening on TCP 4421?
sudo ss -tlnp 'sport = :4421'
Linux / macOS: which process owns the port
sudo lsof -nP -i :4421
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':4421 '
Windows (Command Prompt)
netstat -ano | findstr :4421
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 4421 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 4421
From Windows
Test-NetConnection HOST -Port 4421

Block port 4421 in the firewall

ufw
sudo ufw deny 4421/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 4421 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 4421 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 4421' -Direction Inbound -Protocol TCP -LocalPort 4421 -Action Block

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