Port 223

cdc · TCP/UDP

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

Frequently asked questions

What is port 223 used for?

Port 223 is registered with the IANA for cdc (TCP/UDP). Description: Certificate Distribution Center.

Is port 223 a well-known port?

Yes. Port 223 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 223 is open?

Locally on Linux with ss -tulpn | grep ':223\b', on Windows with netstat -ano | findstr :223. To test a remote host use Test-NetConnection <host> -Port 223 in PowerShell or nc -zv <host> 223 on Linux/macOS.

How do I open port 223 in the firewall?

Ubuntu/Debian (ufw): sudo ufw allow 223/tcp. Fedora/RHEL (firewalld): sudo firewall-cmd --add-port=223/tcp --permanent, then firewall-cmd --reload. Windows (PowerShell as administrator): New-NetFirewallRule -DisplayName "Port 223" -Direction Inbound -Protocol TCP -LocalPort 223 -Action Allow.

IANA registry entries

ProtocolServiceDescription (IANA)
TCPcdcCertificate Distribution Center
UDPcdcCertificate Distribution Center

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