I am thinking about a new authentication mechanism for GNU Anubis, i.e. without the auth service (Identd). Running an Ident daemon is not always possible. The ESMTP authentication is also not the answer. It is so frustrating, why the creators of socket interface did not think about the remote authentication while using AF_INET? What a pity... Unix(7) says that there is a solution with SCM_CREDENTIALS (SCM_CREDS?) and SO_PASSCRED, but only for AF_LOCAL, and even this isn't much portable. The mechanism for sending unix credentials over the AF_INET would help me a lot!