Port 4503

m-bus-oms · TCP/UDP

RangeRegistered port (1024–49151)
ProtocolTCP/UDP
Servicem-bus-oms
Registered2025-05-19

Frequently asked questions

What is port 4503 used for?

Port 4503 is registered with the IANA for m-bus-oms (TCP/UDP). Description: Reserved; M-Bus-OMS over UDP.

Is port 4503 a well-known port?

No. Port 4503 is in the range 1024–49151 (registered or user ports). Ordinary programs may open it without root privileges.

How do I check whether port 4503 is open?

Locally on Linux with ss -tulpn | grep ':4503\b', on Windows with netstat -ano | findstr :4503. To test a remote host use Test-NetConnection <host> -Port 4503 in PowerShell or nc -zv <host> 4503 on Linux/macOS.

How do I open port 4503 in the firewall?

Ubuntu/Debian (ufw): sudo ufw allow 4503/tcp. Fedora/RHEL (firewalld): sudo firewall-cmd --add-port=4503/tcp --permanent, then firewall-cmd --reload. Windows (PowerShell as administrator): New-NetFirewallRule -DisplayName "Port 4503" -Direction Inbound -Protocol TCP -LocalPort 4503 -Action Allow.

IANA registry entries

ProtocolServiceDescription (IANA)
TCP–Reserved
UDPm-bus-omsM-Bus-OMS over UDP

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