Port 6623

ktelnet · TCP/UDP

RangeRegistered port (1024–49151)
ProtocolTCP/UDP
Servicektelnet
Registered2005-08

Frequently asked questions

What is port 6623 used for?

Port 6623 is registered with the IANA for ktelnet (TCP/UDP). Description: Kerberos V5 Telnet.

Is port 6623 a well-known port?

No. Port 6623 is in the range 1024–49151 (registered or user ports). Ordinary programs may open it without root privileges.

How do I check whether port 6623 is open?

Locally on Linux with ss -tulpn | grep ':6623\b', on Windows with netstat -ano | findstr :6623. To test a remote host use Test-NetConnection <host> -Port 6623 in PowerShell or nc -zv <host> 6623 on Linux/macOS.

How do I open port 6623 in the firewall?

Ubuntu/Debian (ufw): sudo ufw allow 6623/tcp. Fedora/RHEL (firewalld): sudo firewall-cmd --add-port=6623/tcp --permanent, then firewall-cmd --reload. Windows (PowerShell as administrator): New-NetFirewallRule -DisplayName "Port 6623" -Direction Inbound -Protocol TCP -LocalPort 6623 -Action Allow.

IANA registry entries

ProtocolServiceDescription (IANA)
TCPktelnetKerberos V5 Telnet
UDPktelnetKerberos V5 Telnet

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