Overview

This article explains how to block all web mail except for a certain Google domain. Users will no longer be able to access their private email accounts and can only log onto a Gmail for a custom domain.

The following sections are covered:

• How to block web mail
• Allow custom Google Domain
• Related information
• Feedback and contact

Applies to the following Sophos products and versions
Sophos Firewall

How to block web mail

1. Navigate to Firewall
2. Click +Add Firewall rule or edit an existing one.
3. Create a firewall rule as shown below:

Create a URL group

Before blocking all web mail we must create a URL group so that Gmail traffic can still go through.

1. Navigate to Web > URL Groups.
2. Create a URL group called Gmail that includes the following domains:
• mail.google.com
• googlemail.com
• gmail.com
  

3. Click Save.

Allow custom Google Domain

1. Navigate to Web > Policies.
2. Edit the No Web Mail policy used in the firewall rule above.
3. Click Add Rule to place a new rule above the No Web Mail rule.
4. Change the rule to add the Gmail URL group and set to Allow.
5. Make sure the toggle next to both rules is turned to the on position (see screenshot below).
6. Open up the Advanced Settings option at the bottom of the policy edit screen.
7. Enable Restrict login domains for Google Apps by checking the box.
8. Next to Allowed domain(s) type in the domain that is allowed to access Google Apps despite the web mail block.

Related information

• Sophos XG Firewall: Web Filtering Basics
• Sophos XG Firewall: How to restrict Gmail access to a custom domain
• G Suite Sync for Microsoft Outlook: Troubleshoot network traffic issues

Feedback and contact

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