[Freeswitch-users] Question about user authentication on 301 redirect

Hi, I have openser set up as sip registrar, location, and redirect server. When a INVITE is received in openser, it would send back a 301 to redirect the user agent to one of the freeswitch servers. The question I have is that what mechanism can be used within freewitch to tell whether the incoming request is redirected from openser( user agents that have already)? In that case, does it mean freeswitch would have to authenticate the user agent again? Thanks for your suggestion. JB