This specifies that the Handler is to be authenticated with an
<AuthBy> clause that is defined elsewhere. The argument must specify
the Identifier of the AuthBy clause to use. The AuthBy clause may be
defined anywhere else: at the top level, or in a Realm or Handler clause.
You can have as many AuthBy parameters as you wish. They will be used in
the order that they appear in the configuration file (subject to
AuthByPolicy) in the same way as <AuthBy > clauses.
Tip
This is a convenient way to reuse the same authenticator for
many Realms or Handlers.
<AuthBy xxxxxx>
Identifier myidentifier
</AuthBy>
<Realm xxxxxx>
# This authenticates through the AuthBy defined above
AuthBy myidentifier
</Realm>
