Port 688
realm-rusd · TCP/UDP
| Range | System/well-known port (0–1023) |
|---|---|
| Protocol | TCP/UDP |
| Service | realm-rusd |
Frequently asked questions
What is port 688 used for?
Port 688 is registered with the IANA for realm-rusd (TCP/UDP). Description: ApplianceWare managment protocol.
Is port 688 a well-known port?
Yes. Port 688 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 688 is open?
Locally on Linux with ss -tulpn | grep ':688\b', on Windows with netstat -ano | findstr :688. To test a remote host use Test-NetConnection <host> -Port 688 in PowerShell or nc -zv <host> 688 on Linux/macOS.
How do I open port 688 in the firewall?
Ubuntu/Debian (ufw): sudo ufw allow 688/tcp. Fedora/RHEL (firewalld): sudo firewall-cmd --add-port=688/tcp --permanent, then firewall-cmd --reload. Windows (PowerShell as administrator): New-NetFirewallRule -DisplayName "Port 688" -Direction Inbound -Protocol TCP -LocalPort 688 -Action Allow.
IANA registry entries
| Protocol | Service | Description (IANA) |
|---|---|---|
| TCP | realm-rusd | ApplianceWare managment protocol |
| UDP | realm-rusd | ApplianceWare managment protocol |