Cisco Cisco Web Security Appliance S670 Guida Utente
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AsyncOS 8.7 for Cisco Web Security Appliances User Guide
Chapter 4 Intercepting Web Requests
Using PAC Files with Client Applications
Client Options For Finding Proxy Auto-Config (PAC) Files
If you choose to use PAC files for your clients, you must also choose how clients will find the PAC files.
You have two options:
You have two options:
•
Configure client with the PAC file location. Configure the client with a URL that specifically
points to the PAC file.
points to the PAC file.
•
Configure clients to detect the PAC file location automatically. Configure clients to find PAC
files automatically using the WPAD protocol along with DHCP or DNS.
files automatically using the WPAD protocol along with DHCP or DNS.
Automatic PAC File Detection
WPAD is a protocol that allows the browser determine the location of a PAC file using DHCP and DNS.
•
To use WPAD with DHCP, you must set up option 252 on the DHCP server’s with the url of the
PAC file location. Not all browsers support DHCP, however.
PAC file location. Not all browsers support DHCP, however.
•
To use WPAD with DNS, you must configure a DNS record to point to the PAC file’s host server.
You can configure either or both options. WPAD will first try to find PAC files using DHCP, and if it
cannot, it will then try DNS.
cannot, it will then try DNS.
Related Topics
•
Hosting PAC Files on the Web Security Appliance
Step 1
Choose Security Services > PAC File Hosting
Step 2
Click Enable and Edit Settings.
Step 3
(Optional) Complete the following basic settings:
Step 4
Click Browse in the PAC Files section and select a PAC file from your local machine for upload to the
Web Security appliance.
Web Security appliance.
Note
If the file you select is called
default.pac
, you do not have to specify the file name when
configuring its location in a browser. The Web Security appliance looks for a file called
default.pac
if no name is specified.
Step 5
Click Upload to upload the PAC file selected in step 4 to the Web Security appliance.
Option
Description
PAC Server Ports
The ports that the Web Security appliance will use to listen for PAC file
requests.
requests.
PAC File Expiration
Allows the PAC file to expire after a specified number of minutes in the
browser’s cache.
browser’s cache.