Ways to block Google Webmail Chat (Chat Embedded in Webmail)
The chat application within Gmail.com (mail.google.com), iGoogle.com (google.com/ig) or Google+ (plus.google.com) uses either HTTP or HTTPS depending on how users have configured their Google Mail settings. When the user logs in the chat application is loaded, as of this writing, from talkgadget.google.com or chatenabled.mail.google.com. The objective is to block Gmail Chat without affecting other webmail features of Gmail. This article illustrates the different methods available in the SonicWall UTM appliance to block it.
Note: Some of the solutions listed here are browser dependent and may not work with some browsers.
As of this writing, App Control Advanced does not have a signature to block HTTP Gmail Chat.
Block Gmail Chat using CFS
When using HTTPS
From SonicOS 5.8.x onwards, SonicWall CFS (CFS 3.0) has the Enable HTTPS Content Filtering feature. In this feature, CFS inspects the Server Name Extension within the Client Hello message and the Certificate CN within the Server Certificate message. Enable this option and enter talkgadget.google.com under Forbidden Domains.