We use MWG7 with Exchange2007+2013. we use explicit proxy mode in HA with 2 nodes and aprx 3000 users.
PC use IE with autoconfig script via proxy.pac file. The point is that this proxy.pac order user to go direct to URL autodiscover.domain.com without proxy server.
This way the PC starts, than reads pac file. When Outlook starts, it uses Windows IE setting to reach internet. autodiscovery URL is constructeed based on user smtp email address and PC tries to connect to autodiscover.domain.com this URL is resolved as internal 10.x.x.x subnet the PAC file directs such subnet go direct. So Outlook tries to contact exchange server via internal LAN not via proxy and internet.
Works ok in whole WAN.
Thanks, the McAfee support team don't seems to know the Exchange Outlook Anywhere authentication process, so i had to exclude the autodiscover.domain.com from proxy in our proxy.pac, as you...
But, our policy is to route all traffic in our proxies, so i hope the support will find something.