Home : File Types : PAC File

.PAC File Extension

File Type 1Proxy Auto-Config File

3.8 (64 Votes)
CategoryWeb Files

What is a PAC file?

A PAC file is a configuration file used by web browsers to select an appropriate proxy server. It contains one or more JavaScript functions with one of them named FindProxyForURL, which defines rules for choosing a proxy server based on a given URL. PAC files are used for controlling and load-balancing Internet traffic, especially in corporate environments.

More Information

PAC files are enabled in web browsers by entering the PAC file URL in the proxy connection settings, or by using the Web Proxy Auto-Discovery (WPAD) protocol. When executed, a PAC file returns a string with one or more proxy server URLs. PAC files are typically hosted on a web server and are named proxy.pac.

Since PAC files contain the configuration in plain text. You can use a text editor, such as Microsoft Notepad or Apple TextEdit to view or modify the files.

NOTE: The PAC file format was originally released in 1996 for use by Netscape Navigator 2.0.

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Programs that open PAC files

Included with OS
Updated 8/7/2019

File Type 2PAC Subtitles File

DeveloperScreen Subtitling Systems
3.8 (19 Votes)
CategoryVideo Files

.PAC File Association 2

Proprietary subtitles format created by Screen Subtitling Systems; used for synchronizing closed captions with a video timeline; can be edited with subtitle editing software such as EZTitles and converted to more standard formats, including .SRT and .SUB.

Programs that open PAC files

Updated 2/7/2018

File Type 3SBStudio II Song File

2.9 (11 Votes)
CategoryAudio Files

.PAC File Association 3

Song format, called a PAC or package file, used by SBStudio; made up of data blocks that store song information and audio data.

Programs that open PAC files

SBStudio II
Updated 2/24/2010

File Type 4STAD Graphic File

2.3 (12 Votes)
CategoryRaster Image Files

.PAC File Association 4

Image format used by the STAD program for Atari ST systems; saved as a black and white image with a resolution of 640x400 pixels; considered a high-resolution graphic for Atari computers.

Programs that open PAC files

Updated 2/24/2010

About PAC Files

Our goal is to help you understand what a file with a *.pac suffix is and how to open it.

All file types, file format descriptions, and software programs listed on this page have been individually researched and verified by the FileInfo team. We strive for 100% accuracy and only publish information about file formats that we have tested and validated.

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