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auth_krb5(8) [centos man page]

AUTH_KRB5(8)						    InterNetNews Documentation						      AUTH_KRB5(8)

auth_krb5 - nnrpd Kerberos v5 authenticator 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 Kerberos v5 TGT to confirm that they are valid. As such, this authenticator 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 TLS to protect the password from sniffing. Normally, you do not want to use this authenticator. Instead, use ckpasswd with PAM support and configure the nnrpd PAM stack to use a Kerberos PAM module. A full Kerberos PAM module is more sophisticated about how it validates passwords and has a much broader array of options than this authenticator. 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 authentication 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 successfully 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 acceptable realms or a -r flag specifying the realm in which to attempt authentication). It's not clear the right thing to do when the username passed in contains a "/" and -i was also given. Right now, auth_krb5 will create a malformed Kerberos principal with multiple instances and attempt to authenticate against it, which will fail but perhaps not with the best error message. HISTORY
Originally written by Christopher P. Lindsey. This documentation was written by Russ Allbery <> based on Christopher's original README file. $Id: auth_krb5.pod 8595 2009-08-21 08:29:26Z iulius $ SEE ALSO
ckpasswd(8), nnrpd(8), readers.conf(5). The latest version of Christopher's original nnrpkrb5auth may be found on his web site at <>. INN 2.5.3 2009-09-11 AUTH_KRB5(8)

Check Out this Related Man Page

RADIUS(8)						    InterNetNews Documentation							 RADIUS(8)

radius - nnrpd RADIUS password authenticator SYNOPSIS
radius [-h] [-f config] DESCRIPTION
radius is an nnrpd authenticator, accepting a username and password from nnrpd (given to nnrpd by a reader connection) and attempting to authenticate that username and password against a RADIUS server. See readers.conf(5) for more information on how to configure an nnrpd authenticator. It is useful for a site that already does user authentication via RADIUS and wants to authenticate news reading connections as well. By default, radius reads pathetc/radius.conf for configuration information, but a different configuration file can be specified with -f. See radius.conf(5) for a description of the configuration file. OPTIONS
-f config Read config instead of pathetc/radius.conf for configuration information. -h Print out a usage message and exit. EXAMPLE
The following readers.conf(5) fragment tells nnrpd to authenticate all connections using this authenticator: auth radius { auth: radius default: <FAIL> default-domain: } "" will be appended to the user-supplied identity, and if RADIUS authentication failes, the user will be assigned an identity of "<FAIL>". BUGS
It has been reported that this authenticator doesn't work with Ascend RADIUS servers, but does work with Cistron RADIUS servers. It's also believed to work with Livingston's RADIUS server. Contributions to make it work better with different types of RADIUS servers would be gratefully accepted. This code has not been audited against the RADIUS protocol and may not implement it correctly. HISTORY
The RADIUS authenticator was originally written by Aidan Cully. This documentation was written by Russ Allbery <>. $Id: radius.pod 7664 2007-09-02 12:58:07Z iulius $ SEE ALSO
nnrpd(8), radius.conf(5), readers.conf(5) RFC 2865, Remote Authentication Dial In User Service. INN 2.5.3 2009-05-21 RADIUS(8)

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