You can specify the source from where you want to obtain virus definitions as follows:
Symantec Web site
Downloads the virus definitions directly from the Symantec LiveUpdate server.
This option is the default setting.
If your organization has several appliances, you can obtain definitions on an internal server. Then you can disseminate the definitions to all of your Symantec Messaging Gateway appliances. This configuration lets you limit the amount of Internet traffic that accesses Symantec LiveUpdate. In this scenario, you must specify the information for the LAN host and proxy, if required.
The LAN host option is unavailable when you select the option to Enable Rapid Response updates.