12/20/2019 323 People found this article helpful 465,778 Views
This article shows how to block HTTPS websites using CFS3.0 (SonicOS 6.2.5.3 or earlier).
The earlier IP based HTTPS filtering filtered HTTPS traffic based on server IP addresses. The enhancement described here is applicable to both IP addresses and hostnames for rating HTTPS websites. HTTPS Content Filtering is applicable for the domains entered in the Custom List and the Match Objects entries in Allowed/Forbidden List under Firewall | Match Objects page. In other words, when Enable HTTPS Content Filtering is checked under CFS | Configure | CFS window , it is a global CFS setting applicable to the following:
Hostnames are obtained in two ways:
EXAMPLE: To blockGmail.com, addmail.google.com in theForbidden Domainsbox. This would block any HTTP host with mail.google.com in the URL. Further, if using HTTPS, CFS will examine the Server Extensions field in the Client Hello message and/or the CN in the Server Hello message and block the page if it matches google.com. In the case of Gmail.com the CN is www.google.com and will be blocked by CFS. The downside of this would be that any Google services using that CN would also be blocked.
Enabling HTTPS Content Filter Globally
Adding Allow/Forbidden Custom List in CFS via Users and Zone Screens
Configuring Custom CFS Policies to inherit the Allow/Forbidden Custom List.
What has been entered under the forbidden domains is automatically applicable to the default policy. To enforce the same on custom CFS policies their Custom List Settings needs to be manually set to Global.
Adding Allow/Forbidden Custom List to CFS using App Rules
Match Objects
To create a custom list of allowed or forbidden domains, select CFS Allow/Forbidden List under Match Object Type. You could also load the allow/block list from a file containing the name of the domains. Each entry in the file should be separated by a line. The maximum size of the file is 8192 bytes.
Unlike CFS via Users and Zones, Custom List Objects (as above) cannot be used individually in an App Rule. It can only be used with a CFS Category List Object (see below):
App Rules
Log Messages
When SonicWall CFS blocks HTTPS websites users will not see a blocked page only a connection-reset page.
However the following messages will appear in the logs: