Port 9903
multicast-ping · TCP/UDP
| Range | Registered port (1024–49151) |
|---|---|
| Protocol | TCP/UDP |
| Service | multicast-ping |
| Reference | RFC 6450 |
| Modified | 2011-12-09 |
Frequently asked questions
What is port 9903 used for?
Port 9903 is registered with the IANA for multicast-ping (TCP/UDP). Description: Reserved; Multicast Ping Protocol.
Is port 9903 a well-known port?
No. Port 9903 is in the range 1024–49151 (registered or user ports). Ordinary programs may open it without root privileges.
How do I check whether port 9903 is open?
Locally on Linux with ss -tulpn | grep ':9903\b', on Windows with netstat -ano | findstr :9903. To test a remote host use Test-NetConnection <host> -Port 9903 in PowerShell or nc -zv <host> 9903 on Linux/macOS.
How do I open port 9903 in the firewall?
Ubuntu/Debian (ufw): sudo ufw allow 9903/tcp. Fedora/RHEL (firewalld): sudo firewall-cmd --add-port=9903/tcp --permanent, then firewall-cmd --reload. Windows (PowerShell as administrator): New-NetFirewallRule -DisplayName "Port 9903" -Direction Inbound -Protocol TCP -LocalPort 9903 -Action Allow.
IANA registry entries
| Protocol | Service | Description (IANA) |
|---|---|---|
| TCP | – | Reserved |
| UDP | multicast-ping | Multicast Ping Protocol |