Server - How to Pass proxy.pac script to client with DHCP

If your company has proxy to browse internally and externally thought internet your problem would be to publish automatically that to clients.

There are several ways to deploy proxy to client's browser like Wpad, GPO, login script...

One that I would like to focuse is DHCP with option 252 that will pass to clients a proxy.pac script that, depending on which subnet client is, will setting up a differently proxy to clients.

proxy.pac can be published in several ways:

1. Distribute the tested proxy.pac file either by emailing it to your users or by posting it on an internal web server.
2. Distribute the configuration as a wpad.dat file, which is documented in the Publishing Proxy Information as a wpad.datFile Knowledgebase article. 
3. Enforce the proxy configuration by Creating a Group Policy Object (GPO) on your Active Directory server. 

Here they are some articles useful:

Sophos Web Appliance: Creating, Testing, and Deploying a proxy.pac File

Create a WPAD Entry in DHCP

Configuring Users' Browsers to Use the Web Appliance with a Group Policy Object

Publishing Automatic Proxy Information as a wpad.dat file

Configuring your network for Explicit Deployment

Debug PAC File