Port 401

ups · TCP/UDP

RangeSystem/well-known port (0–1023)
ProtocolTCP/UDP
Serviceups
Registered2008-08-29

Frequently asked questions

What is port 401 used for?

Port 401 is registered with the IANA for ups (TCP/UDP). Description: Uninterruptible Power Supply.

Is port 401 a well-known port?

Yes. Port 401 is in the range 0–1023 (system or well-known ports). On Linux and macOS only privileged processes may bind to these ports.

How do I check whether port 401 is open?

Locally on Linux with ss -tulpn | grep ':401\b', on Windows with netstat -ano | findstr :401. To test a remote host use Test-NetConnection <host> -Port 401 in PowerShell or nc -zv <host> 401 on Linux/macOS.

How do I open port 401 in the firewall?

Ubuntu/Debian (ufw): sudo ufw allow 401/tcp. Fedora/RHEL (firewalld): sudo firewall-cmd --add-port=401/tcp --permanent, then firewall-cmd --reload. Windows (PowerShell as administrator): New-NetFirewallRule -DisplayName "Port 401" -Direction Inbound -Protocol TCP -LocalPort 401 -Action Allow.

IANA registry entries

ProtocolServiceDescription (IANA)
TCPupsUninterruptible Power Supply
UDPupsUninterruptible Power Supply

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