Cisco Cisco Web Security Appliance S670 User Guide
Chapter 5 Web Proxy Services
Working with PAC Files
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Cisco IronPort AsyncOS 7.1 for Web User Guide
OL-23207-01
Creating a PAC File for Remote Users
Some laptop users connect to the Internet both from inside your organization’s
network and outside the network. For these users, you can create a PAC file that
informs the browser to connect to the Web Proxy when they are on the network,
and to connect directly to web servers when they are not on the network.
network and outside the network. For these users, you can create a PAC file that
informs the browser to connect to the Web Proxy when they are on the network,
and to connect directly to web servers when they are not on the network.
To do this, make sure the PAC file is hosted on a web server that is DNS resolvable
inside the network, but not DNS resolvable outside the network. This works
because when you enter a URL for the PAC file location, the browser will always
try to use the PAC file in the configured location. If the browser cannot resolve
the URL, such as when it is outside the network, it tries to access all web sites
directly instead. Then when the laptop connects to the network again, the browser
can access the PAC file and will use the Web Proxy to access web sites.
inside the network, but not DNS resolvable outside the network. This works
because when you enter a URL for the PAC file location, the browser will always
try to use the PAC file in the configured location. If the browser cannot resolve
the URL, such as when it is outside the network, it tries to access all web sites
directly instead. Then when the laptop connects to the network again, the browser
can access the PAC file and will use the Web Proxy to access web sites.
Specifying the PAC File in Browsers
To use a PAC file, you must publish the PAC file in a location that can be accessed
by each browser that needs to access it. When you configure a browser to use a
PAC file, you can use either of the following methods:
by each browser that needs to access it. When you configure a browser to use a
PAC file, you can use either of the following methods:
•
Enter the PAC file location. See
•
Detect the PAC file location automatically. See
.
Entering the PAC File Location
You can configure a browser to use a PAC file by specifying the exact location of
the file. You might want to enter the exact PAC file location for laptop users who
might need to use different proxy servers depending on their current location.
the file. You might want to enter the exact PAC file location for laptop users who
might need to use different proxy servers depending on their current location.
You can place the PAC file in the following locations:
•
Local machine. You can place the PAC file on each client machine and
configure the browsers to use it. You might want to use a local PAC file to test
a PAC file before deploying it to the entire organization. Enter the path in the
browser configuration. The path you enter depends on the browser type.
configure the browsers to use it. You might want to use a local PAC file to test
a PAC file before deploying it to the entire organization. Enter the path in the
browser configuration. The path you enter depends on the browser type.