I did a proof of concept with Spring Security in order to perform pre authentication by using the PRE\_AUTH\_FILTER filter. It worked OK, but I'd like to know if I can redirect to the login page if the this filter does not work, because I get HTTP 403.  

I mean, if the initial request does not contain the SM\_USER field in the header, how can I redirect to the login page? I need to consider these two scenarios (when it contains the field - SM\_USER -, and when not) and I was not able to get it working. Any ideas about it?