Port 523

ibm-db2 · TCP/UDP

RangeSystem/well-known port (0–1023)
ProtocolTCP/UDP
Serviceibm-db2

Frequently asked questions

What is port 523 used for?

Port 523 is registered with the IANA for ibm-db2 (TCP/UDP). Description: IBM-DB2.

Is port 523 a well-known port?

Yes. Port 523 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 523 is open?

Locally on Linux with ss -tulpn | grep ':523\b', on Windows with netstat -ano | findstr :523. To test a remote host use Test-NetConnection <host> -Port 523 in PowerShell or nc -zv <host> 523 on Linux/macOS.

How do I open port 523 in the firewall?

Ubuntu/Debian (ufw): sudo ufw allow 523/tcp. Fedora/RHEL (firewalld): sudo firewall-cmd --add-port=523/tcp --permanent, then firewall-cmd --reload. Windows (PowerShell as administrator): New-NetFirewallRule -DisplayName "Port 523" -Direction Inbound -Protocol TCP -LocalPort 523 -Action Allow.

IANA registry entries

ProtocolServiceDescription (IANA)
TCPibm-db2IBM-DB2
UDPibm-db2IBM-DB2

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