From the virtual server page, click the Content Management tab.
Click General sub tab.
Go to Compression > Precompressed Content section and select from the following options.
Precompressed Content — Enable/Disable. Allows you to instruct the server to serve pre-compressed content for the selected resource.
Age Checking — Specify whether to check if the compressed version is older than the non-compressed version.
If selected, then the compressed version, even if it is older than the non-compressed version, will not be selected.
If not selected, then the compressed version, even if it is older than the non-compressed version, will always be selected.
Insert Vary Header — Specifies whether to use a Vary: Accept-encoding header.
If selected, then a Vary: Accept-encoding header is always inserted when a compressed version of a file is selected.
If not selected, then a Vary: Accept-encoding header is never inserted.
Click Save.