FindProxyForURL is a practical resource for deploying and maintaining Proxy Automatic Configuration (PAC) files. Whether creating a PAC file for the first time, looking to simplify a PAC file already in deployment, or enabling automatic PAC file discovery using WPAD, can help guide you.

The advice provided herein is based on a decade of experience creating, deploying, and supporting PAC files, often in conjunction with WPAD, across hundreds of organizations using proxies. While the requirements may differ, a straightforward and consistent approach can be taken to the design and maintenance of a PAC file, whether the deployment supports 25 or 90000 employees.

When this website was created there was very little information on PAC and WPAD available, and what was available heavily referenced an unfriendly and outdated 1996 Netscape document. Very little was known or documented as to best practices and even what was supported by the various browsers because after all, the PAC and WPAD technologies never became standardized. With time a wealth of information is now available on the Internet, however, the approaches to many common challenges are at best inconsistent and at their worst hokey, impractical, and risking possible security issues.

The guiding principle of this website is to avoid unnecessary coding and maintenance, to simplify a PAC file to its base elements while retaining functionality and security. By providing this assistance I hope this website can guide you to choosing the best possible PAC file and/or WPAD solution for your organization.

Peter Hayes



30 October 2014 – A diagnostic tool developed by for troubleshooting PAC file and WPAD deployments has been added.
30 November 2012 – A new section, PAC File Deployment, has been added.
29 November 2012 – A new section, Troubleshooting, has been added. This will be expanded over the coming weeks.
31 August 2012 – The Deploying WPAD page has been updated to include browser configuration instructions.