Port 3551

apcupsd · TCP/UDP

RangeRegistered port (1024–49151)
ProtocolTCP/UDP
Serviceapcupsd
Registered2002-07

Frequently asked questions

What is port 3551 used for?

Port 3551 is registered with the IANA for apcupsd (TCP/UDP). Description: Apcupsd Information Port.

Is port 3551 a well-known port?

No. Port 3551 is in the range 1024–49151 (registered or user ports). Ordinary programs may open it without root privileges.

How do I check whether port 3551 is open?

Locally on Linux with ss -tulpn | grep ':3551\b', on Windows with netstat -ano | findstr :3551. To test a remote host use Test-NetConnection <host> -Port 3551 in PowerShell or nc -zv <host> 3551 on Linux/macOS.

How do I open port 3551 in the firewall?

Ubuntu/Debian (ufw): sudo ufw allow 3551/tcp. Fedora/RHEL (firewalld): sudo firewall-cmd --add-port=3551/tcp --permanent, then firewall-cmd --reload. Windows (PowerShell as administrator): New-NetFirewallRule -DisplayName "Port 3551" -Direction Inbound -Protocol TCP -LocalPort 3551 -Action Allow.

IANA registry entries

ProtocolServiceDescription (IANA)
TCPapcupsdApcupsd Information Port
UDPapcupsdApcupsd Information Port

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