Q7250005: What ports do I need to open in the firewall to enable communication between the ActiveXperts Network Monitor server and the monitored servers?
The ports used when monitoring a server using ActiveXperts Network Monitor depend on the type of monitor function that is being done. For example, monitoring a web site usually requires one port - port 80, monitoring an SMTP server requires port 25, monitoring DNS requires port 53(udp).
WMI (or more correctly RPC/DCOM) uses TCP ports 135 and 445 as well as dynamically-assigned ports above 1024. WMI is used for many Windows-based checks.
When checking which ports must be opened on the firewall, one should also take into consideration the ports required to perform the action if the monitoring check fails.
The best practice is to use a packet sniffer like the Microsoft Network Monitor or SolarWinds to see which ports are required.