Adds attributes to the request before passing it to any authentication modules. Unlike AddToRequest, an attribute will only be added if it does not already exist in the request. Value is a list of comma separated attribute value pairs all on one line, exactly as for any reply item. StripFromRequest removes attributes from the request before AddToRequest and AddToRequestIfNotExist adds any to the request. You can use any of the special % formats in the attribute values. There is no default.

# Append a Filter-ID and host name if they are not there already
AddToRequestIfNotExist Calling-Station-Id=1,Login-IP-Host=%h