I solved a GTI communication issue opening all subnets of this article:
Subnets change... so it's better to open all.
There is a command to check connectivity between TIE & GTI cloud via proxy.
curl -kvx proxyip-add:9090 https://tie.gti.mcafee.com:443
This shows connection status, RSA_DES certificate details and communication status.
usually i tried to ping & nslookup.
I sent output of above command to platinum support to know the connection status. Received positive response from McAfee.
Also we can check on ePO console - reputation and GTI last communication.
my issue is resolved now.