You are running into the application cert pinning I think, I've seen this on a few IOS/android apps but makes sense here as well, and I've confirmed that is what they are doing as well in the following link: http://googleonlinesecurity.blogspot.com/2013/05/changes-to-our-ssl-certificates.html At this time, Google Drive's PC application does not support SNI and performs some degree of certificate pinning for transfers.  (This is going to cause you a lot of issues with SSL MITM setups). One fairly easy way to work around this is with a DNS based filter and with pfSense you can easily control what DNS server a client is using. Thanks, Adam

thanks for your response, I will look and review what you say, I'm hoping to solve this problem, otherwise im gonna give a shot with lusca.