Spam filtering is
the ability to dynamically block emails that are not from a known or trusted
source or that have inappropriate content. Spam filtering requires an
associated business logic that indicates that a particular kind of message is
spam. When the NetScaler appliance processes Outlook Web Access (OWA) messages
based on the HTTP protocol, HTTP callouts can be used to filter spam.
You can use HTTP
callouts to extract any portion of the incoming message and check with an
external callout server that has been configured with rules that are meant for
determining whether a message is legitimate or spam. In case of spam email, for
security reasons, the NetScaler appliance does not notify the sender that the
email is marked as spam.
example conducts a very basic check for various listed keywords in the email
subject. These checks can be more complex in a production environment.
To implement this
configuration, you must perform the following tasks: