Ways to block Google Webmail Chat (Chat Embedded in Webmail)

03/26/2020 1192 14521

DESCRIPTION:
Ways to block Google Webmail Chat (Chat Embedded in Webmail)

RESOLUTION:

Feature/Application:

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.

Procedure:

Block Gmail Chat using Application Firewall
Block Gmail Chat using App Control Advanced Signatures
Block Gmail Chat using CFS

Block Gmail Chat using Application Firewall

Create the following Match Object under Firewall > Match Objects (or Application Firewall > Match Objects depending on the SonicOS Enhanced firmware)

Create the following App Rule under Firewall > App Rules (or Application Firewall > Policies depending on the SonicOS Enhanced firmware)

Please refer KB article, UTM: Using Application Firewall to Block chat embedded within Gmail while still having the mails working for a different method.

Block Gmail Chat using App Control Advanced Signatures

When using HTTPS

Use the Signature ID 3440 in Firewall > App Control Advanced (or Security Services > Application Control depending on the SonicWall UTM appliance).
Refer this KB article for detailed steps: UTM: How to Block Gmail Chat inside Gmail (Google Mail) using Application Control (5.8 onwards) .

When using HTTP

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.

When using HTTP

Follow this KB article to block Gmail Chat when using HTTP: UTM - CFS: Blocking Gmail Chat in Google Webmail using CFS