Port 400

osb-sd · TCP/UDP

RangeSystem/well-known port (0–1023)
ProtocolTCP/UDP
Serviceosb-sd
Registered2008-06-06
Modified2023-12-27

Frequently asked questions

What is port 400 used for?

Port 400 is registered with the IANA for osb-sd (TCP/UDP). Description: Oracle Secure Backup.

Is port 400 a well-known port?

Yes. Port 400 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 400 is open?

Locally on Linux with ss -tulpn | grep ':400\b', on Windows with netstat -ano | findstr :400. To test a remote host use Test-NetConnection <host> -Port 400 in PowerShell or nc -zv <host> 400 on Linux/macOS.

How do I open port 400 in the firewall?

Ubuntu/Debian (ufw): sudo ufw allow 400/tcp. Fedora/RHEL (firewalld): sudo firewall-cmd --add-port=400/tcp --permanent, then firewall-cmd --reload. Windows (PowerShell as administrator): New-NetFirewallRule -DisplayName "Port 400" -Direction Inbound -Protocol TCP -LocalPort 400 -Action Allow.

IANA registry entries

ProtocolServiceDescription (IANA)
TCPosb-sdOracle Secure Backup
UDPosb-sdOracle Secure Backup

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