This optional parameter can be used to specify one or more rewriting rules which will be used to rewrite the Realm name used by Resolver to discover the appropriate target server.

# Find the target server for users@uninett.no by looking up 
# as if it were @no.eduroam.org
RewriteTargetRealm s/uninett.no/no.eduroam.org/

You can also set up a default realm that will be used if there is no realm in the user name after rewriting by having the last RewriteTargetRealm like this:

RewriteTargetRealm s/^$/default.realm.com/