Hi, there! I’m Peter Hayes.

In 2007, I joined ScanSafe (later acquired by Cisco) as a support engineer, one of the first companies in an emerging industry to deliver web security for users through a cloud-based multi-tenant proxy. Years later, I had multiple roles at a competing cloud company, Zscaler, where I successfully supported and deploy hundreds of customers and later moved to a role in enablement where I had the opportunity to pass on all that I had learned over the past 15 years.

During all that time, no matter the advancements in product and technology, PAC files never went away, and to this day thousands of businesses, whether using an on-premise proxy or cloud-based solution, are at least partly leveraging a PAC file-based deployment.

In my numerous prospect and customer-facing roles since first creating this website I’ve often worked with IT and network security departments who didn’t know I was the author and I’ve been thrilled at both the positive impact and the need to keep online and updated.


The goal of is to be a concise and clear resource, enabling others to deploy effective PAC file solutions, free of myth, and without complexity.

As a support engineer working with PAC files back in 2007, I sought any kind of authoritative source for documentation and troubleshooting. At the time the best resources were the odd page or two found in the online support portal of various proxy vendors – nothing that would enable anyone to get started with PAC files or avoid common pitfalls. The best I could find was a dusty Netscape development manual from 1995! As such, the drive has always been to maintain a PAC file resource that felt complete and would remain online for as long as others found it useful.