SYNOPSIS

       auth_krb5 [-i instance]

DESCRIPTION

       This program does authentication for nnrpd against a Kerberos v5 KDC.
       This is NOT real Kerberos authentication using service tickets;
       instead, a username and password is used to attempt to obtain a Ker-
       beros v5 TGT to confirm that they are valid.  As such, this authentica-
       tor assumes that nnrpd has been given the user's username and password,
       and therefore is not as secure as real Kerberos authentication.  It
       generally should only be used with NNTP over SSL to protect the pass-
       word from sniffing.

OPTIONS

       -i instance
           If this option is given, instance will be used as the instance of
           the principal received from nnrpd and authentication will be done
           against that principal instead of the base principal.  In other
           words, a principal like "user", when passed to auth_krb5 invoked
           with "-i nntp", will be transformed into "user/nntp" before
           attempting Kerberos authentication.

           Since giving one's password to nnrpd is not as secure as normal
           Kerberos authentication, this option supports a configuration where
           all users are given a separate instance just for news authentica-
           tion with its own password, so their regular account password isn't
           exposed via NNTP.

EXAMPLE

       The following readers.conf(5) fragment tells nnrpd to authenticate
       users by attempting to obtain Kerberos v5 TGTs for them, appending an
       instance of "nntp" to usernames before doing so:

           auth kerberos {
               auth: "auth_krb5 -i nntp"
           }

           access kerberos {
               users: "*/nntp"
               newsgroups: example.*
           }

       Access is granted to the example.* groups for all users who success-
       fully authenticate.

BUGS

       Currently, any username containing realm information (containing "@")
       is rejected.  This is to prevent someone from passing in a username
       corresponding to a principal in another realm that they have access to
       and gaining access to the news server via it.  However, this is also
       something that people may wish to do under some circumstances, so there
       should be a better way of handling it (such as, perhaps, a list of
       $Id: auth_krb5.8 5912 2002-12-03 05:31:11Z vinocur $

SEE ALSO

       nnrpd(8), readers.conf(5)

       The latest version of Christopher's original nnrpkrb5auth may be found
       on his web site at <http://www.mallorn.com/tools/>.



INN 2.4.0                         2002-12-02                      AUTH_KRB5(8)