Cisco Cisco Email Security Appliance C650 Guida Utente

 describes the update settings you can configure. 

Choose whether to download service update and Cisco IronPort AsyncOS 
upgrade images from the IronPort update servers or a local web server.

The default is the IronPort update servers. In addition to AsyncOS 
upgrades, these servers are used to obtain update images for Sophos and 
McAfee Anti-Virus definitions, IronPort Anti-Spam and IronPort 
Intelligent Multi-Scan rules, Outbreak Filter rules, time zone rules, feature 
key updates, and PXE Engine updates.

You might want to choose a local web server under either of the following 
circumstances:

You want to download the upgrade and update images from IronPort, 
but you need to enter a static address provided by Cisco IronPort 
Customer Support.

You want to temporarily download an upgrade image stored on a local 
web server. After you download the image, Cisco recommends 
changing this setting back to the IronPort update servers (or the static 
address if you used that) so that security components continue to update 
automatically.

When you choose a local update server, enter the base URL and port number 
for the servers used to download the upgrades and updates. If the server 
requires authentication, you can also enter a valid user name and password.

IronPort Intelligent Multi-Scan requires a second local server to 
download updates for third-party anti-spam rules.