OK, this isn’t listed anywhere on GFI’s website, and until it is, at least you can find the info here.
If you have a firewall policy in place restricting internet access but still want to allow the GFIMAX agent to run, you need to allow access to:
upload1.systemmonitor.co.uk 94.236.25.147
upload2.systemmonitor.co.uk 94.236.25.149
upload3.systemmonitor.co.uk 94.236.25.146
upload4.systemmonitor.co.uk 94.236.25.148