Configure firewall settings for Zoho Mail
Configure your firewall settings and allow your organization members to access Zoho Mail without any restrictions. All of the below-mentioned domains have to be whitelisted even if you don't see activity at those addresses. Because, even if there is no activity at a point, there are high chances for the links to have future activity. And if you haven't whitelisted any of the domains below, it may result in difficulties to connect with a particular service or more offered by Zoho Mail.
Domains
Exclude TCP and Web Socket protocols for the following domains from your firewall and proxy settings.
- *.zoho.com
- *.zohostatic.com
- *.zohocdn.com
- *.sigmausercontent.com
- https://fonts.gstatic.com
- https://fonts.zohowebstatic.com
- wss://mailws.zoho.com
- wss://mailwsorg.zoho.com
- wss://mailwsfree.zoho.com
Note:
The asterisk (*) can be replaced with any values except for period (.).