This article is intended for users of SymDiag. Though general readers may benefit from the article’s contents, any solutions, insights, or guidance are geared toward those using SymDiag.
If the browser is configured to work with a PAC file yet is unable to download the PAC file, the browser will connect directly to Web sites, i.e. without isolation.
A PAC file, which is a proxy auto-config file, instructs the browser how to handle web requests, i.e., which requests go to proxy, and which ones go directly to the target site. Absence of a PAC file will cause the browser to bypass all proxy configuration. This is likely to result in vulnerability to the end user’s computer.
Make sure there is connectivity on port 8081 between the Web Isolation proxy and the end user’s computer. As a troubleshooting mechanism, copy and paste the PAC file URL into the browser’s address bar and confirm the PAC file is being downloaded.
For further information, see the Symantec Threat Isolation Platform (STIP) Guide for Administrators section on Defining Zones, Gateways, and Associated Components > Defining the Zone.