General settings

The firewall scans HTTP(S) and FTP traffic for threats as specified by your firewall rules and for inappropriate web usage when a web policy is selected for a rule. These settings apply only to traffic that matches firewall rules with these options set. You can specify the type of scanning, maximum file size to be scanned, and additional checking. You can also create policy overrides to allow end users to access otherwise blocked websites.

Malware and content scanning

Configure general restrictions for scanning and restricting traffic by type and protocol.

Scan engine selection
Scanning engine to use on all traffic.
Note If you are using Sandstorm, set the single-scan engine to Sophos or select dual-engine scanning.

Single engine Scan traffic using the primary antivirus engine (by default, Sophos). This selection provides optimal performance.

Dual engine Scan traffic using both engines, first by the primary and then by the secondary. This selection provides maximum recognition rate and security, but may affect performance.

Scanning mode
Scanning mode for HTTP(S) traffic. In batch mode, no part of the downloaded file is passed to the browser until the entire file has been downloaded and scanned. In real-time mode, the downloaded file content is passed to the browser, but will not be completed until scanned and found to be clean. While batch mode offers maximum protection, it may affect browsing performance.
Block potentially unwanted applications
Prevent users from downloading potentially unwanted applications (PUAs).
Authorized PUAs
List of PUAs that you do not want to block.
Action on malware scan failure
Action to take when the firewall encounters content that could not be scanned.
Note Files that cannot be fully scanned because they are encrypted or corrupted may contain undetected threats. Blocking offers the best protection.
Do not scan files larger than
Maximum size of files to be scanned for HTTP(S), in MB. Files that exceed this size will not be scanned.
Note If you are using Sandstorm, this value has been reset to the recommended minimum value.
Maximum file scan size for FTP
Maximum size of files to be scanned for FTP, in MB. Files that exceed this size will not be scanned.
Scan audio and video files
Scan audio and video content for malware and threats. Scanning may cause issues with streaming audio and video.
Enable pharming protection
Pharming attacks redirect users from legitimate websites to fraudulent websites that have been created to look like the legitimate site. Protect users against domain name poisoning attacks by repeating DNS lookups before connecting.

HTTPS decryption and scanning

HTTPS scanning certificate authority (CA)
Certificate authority for securing scanned HTTPS connections.
Block unrecognized SSL protocols
Prevent traffic that avoids HTTPS scanning by using invalid SSL protocols.
Block invalid certificates
Connect only to sites with a valid certificate.
For errors and block/warn policy actions on HTTPS connections when Decrypt and Scan is disabled
When an HTTPS request results in a block or warn policy action where Decrypt and scan HTTPS is disabled, you can either display a notification to the user or drop the connection without a user notification.
Note Browsers may show certificate warnings if the HTTPS CA is not installed.

Policy overrides

Policy overrides allow authorized users to grant temporary access to websites that would normally be blocked by a web policy. Authorized users create policy overrides in the user portal. Overrides specify websites and categories, a time range, and access codes. When an end-user visits a site for which an override is specified, the block page will contain an additional field allowing the end-user to enter an access code.

  • To view and manage the overrides currently specified, click View overrides. These settings allow you to turn overrides on or off and delete overrides.
Enable policy override
Allow authorized users to create web policy overrides in the user portal.
Authorized users and groups
Users and groups that will be able to create and manage overrides.
Blocked websites and categories
Websites and web categories that can never be bypassed by web policy overrides.
Allow manual access code entry
Allow the specified users to create their own access codes in the user portal. If this option is not enabled, users must use generated codes.

Allow access to blocked websites

The following policy override allows users in the Teachers group to permit end-users access to otherwise blocked websites. However, when the override is in effect, end-users will not be able to access websites in the Alcohol & Tobacco category.

Web content caching

Enable web content cache
Keep a copy of recently visited sites to reduce bandwidth consumption and improve performance.
Always cache Sophos Endpoint updates
Keep a copy of Sophos Endpoint Protection updates to improve performance on your network.
Note If this option is turned off you may experience network congestion when many endpoints attempt to download updates from the internet at the same time.

Web proxy configuration

The firewall intercepts traffic transparently and enforces web protection (for example, policies and malware scanning) when the web proxy service is enabled for a network zone. By default, the service is enabled for LAN and Wi-Fi zones. In transparent mode, the firewall allows HTTP traffic on port 80 and HTTPS traffic on port 443 only.

However, you can configure the firewall to act as a proxy for configured web browsers by specifying a web proxy listening port. Users who are behind the proxy must specify the LAN or Wi-Fi address and port in the web proxy configuration settings of their browsers. (Refer to the browser documentation for details.)

Specify the web proxy listening port and allowed destination ports when you want the firewall to act as a web proxy for configured web browsers.

Note IPS policy is applicable on the traffic between proxy and WAN, but not between user and proxy.
Note Traffic shaping policy is not applicable on the direct proxy traffic.
Web proxy listening port
Port on which the web proxy will listen for HTTP connection requests.
Allowed destination ports
The firewall may receive requests to connect to remote servers using a non-standard port. Specify the ports on which the proxy will allow connection. (This setting applies only when the web proxy listening port is set.)
CAUTION Allowing connection on non-standard ports may pose a security risk.