NextAuthenticator
NextAuthenticator(fSuggestedLocalAuthenticator, PPP_LOCAL_SIDE);
authenticator = NextAuthenticator(fPeerAuthenticator, PPP_PEER_SIDE);
authenticator = NextAuthenticator(fPeerAuthenticator, PPP_PEER_SIDE);
KPPPProtocol *NextAuthenticator(const KPPPProtocol *start,