Hello, I'm implementing basic authentication using the auth and auth_db module, and I was wondering which domain to use when calling the auth_check function? Should I use the From domain or the To domain? Or both? The default configuration file deployed with kamailio uses $fd, but a code sample in the htable module page uses $td (dictionary attack sample). Aren't both the From and To header spoofable and not really used in SIP message routing?