'\" te
.\" Copyright (c) 2008, Sun Microsystems, Inc. All Rights Reserved
.\" The contents of this file are subject to the terms of the Common Development and Distribution License (the "License"). You may not use this file except in compliance with the License.
.\" You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE or http://www.opensolaris.org/os/licensing. See the License for the specific language governing permissions and limitations under the License.
.\" When distributing Covered Code, include this CDDL HEADER in each file and include the License file at usr/src/OPENSOLARIS.LICENSE. If applicable, add the following below this CDDL HEADER, with the fields enclosed by brackets "[]" replaced with your own identifying information: Portions Copyright [yyyy] [name of copyright owner]
.TH KCLIENT 8 "November 22, 2021"
.SH NAME
kclient \- set up a machine as a Kerberos client
.SH SYNOPSIS
.nf
\fB/usr/sbin/kclient\fR [\fB-n\fR] [\fB-R\fR \fIrealm\fR] [\fB-k\fR \fIkdc\fR] [\fB-a\fR \fIadminuser\fR]
     [\fB-c\fR \fIfilepath\fR] [\fB-d\fR \fIdnsarg\fR] [\fB-f\fR \fIfqdn_list\fR] [\fB-h\fR \fIlogical_host_name\fR]
     [\fB-k\fR \fIkdc_list\fR] [\fB-m\fR \fImaster_kdc\fR] [\fB-p\fR \fIprofile\fR] [\fB-s\fR \fIpam_service\fR]
     [\fB-T\fR \fIkdc_vendor\fR]
.fi

.SH DESCRIPTION
By specifying the various command options, you can use the \fBkclient\fR
utility to:
.RS +4
.TP
.ie t \(bu
.el o
Configure a machine as a Kerberos client for a specified realm and for KDC by
setting up \fBkrb5.conf\fR(5).
.RE
.RS +4
.TP
.ie t \(bu
.el o
Add the Kerberos host principal to the local host's \fBkeytab\fR file
(\fB/etc/krb5/krb5.keytab\fR).
.RE
.RS +4
.TP
.ie t \(bu
.el o
Set up the machine to do kerberized NFS.
.RE
.RS +4
.TP
.ie t \(bu
.el o
Bring over a master \fBkrb5.conf\fR copy from a specified pathname.
.RE
.RS +4
.TP
.ie t \(bu
.el o
Setup a machine to do server and/or host/domain name-to-realm mapping lookups
by means of DNS.
.RE
.RS +4
.TP
.ie t \(bu
.el o
Configure a Kerberos client to use an MS Active Directory server. This
generates a \fBkeytab\fR file with the Kerberos client's service keys
populated.
.RE
.RS +4
.TP
.ie t \(bu
.el o
Setup a Kerberos client that has no service keys. This is useful when the
client does not require service keys, because the client does not wish to host
a service that uses Kerberos for security.
.RE
.RS +4
.TP
.ie t \(bu
.el o
Configure a Kerberos client that is part of a cluster. This option requires the
logical host name of the cluster so that the proper service keys are created
and populated in the client's \fBkeytab\fR file.
.RE
.RS +4
.TP
.ie t \(bu
.el o
Setup a Kerberos client to join an environment that consists of Kerberos
servers that are non-Solaris and non-MS Active Directory servers.
.RE
.RS +4
.TP
.ie t \(bu
.el o
Configure \fBpam.conf\fR(5) to use Kerberos authentication for specified
services.
.RE
.RS +4
.TP
.ie t \(bu
.el o
Configure the client as a simple NTP broadcast/multicast client.
.RE
.RS +4
.TP
.ie t \(bu
.el o
Specify custom domain/host name-to-realm name mappings.
.RE
.RS +4
.TP
.ie t \(bu
.el o
Setup the Kerberos client to use multiple KDC servers.
.RE
.sp
.LP
The \fBkclient\fR utility needs to be run on the client machine with root
permission and can be run either interactively or non-interactively. In the
non-interactive mode, the user feeds in the required inputs by means of a
profile, command-line options, or a combination of profile and command-line
options. The user is prompted for "required" parameter values (\fBrealm\fR and
\fBadminuser\fR), if found missing in the non-interactive run. The interactive
mode is invoked when the utility is run without any command-line arguments.
.sp
.LP
Both the interactive and non-interactive forms of \fBkclient\fR can add the
\fBhost/fqdn\fR entry to the local host's \fBkeytab\fR file. They also can
require the user to enter the password for the administrative user requested,
to obtain the Kerberos Ticket Granting Ticket (TGT) for \fBadminuser\fR. The
\fBhost/fqdn\fR, \fBnfs/fqdn\fR, and \fBroot/fqdn\fR principals can be added to
the KDC database (if not already present) before their possible addition to the
local host's \fBkeytab\fR.
.sp
.LP
The \fBkclient\fR utility assumes that the local host has been setup for DNS
and requires the presence of a valid \fBresolv.conf\fR(5). Also, \fBkclient\fR
can fail if the localhost time is not synchronized with that of the KDC. For
Kerberos to function the localhost time must be within five minutes of that of
the KDC. It is advised that both systems run some form of time synchronization
protocol, such as the Network Time Protocol (NTP). See the \fBntpd\fR man page,
delivered  in  the  \fBSUNWntpu\fR package (not a SunOS man page).
.SH OPTIONS
The non-interactive mode supports the following options:
.sp
.ne 2
.na
\fB\fB-n\fR\fR
.ad
.sp .6
.RS 4n
Set up the machine for kerberized NFS. This involves making changes to
\fBkrb5*\fR security flavors in \fBnfssec.conf\fR(5). This option will also add
\fBnfs/fqdn\fR and \fBroot/fqdn\fR entries to the local host's \fBkeytab\fR
file if the \fB-K\fR option has not been specified.
.RE

.sp
.ne 2
.na
\fB\fB-R\fR [ \fIrealm\fR ]\fR
.ad
.sp .6
.RS 4n
Specifies the Kerberos realm.
.RE

.sp
.ne 2
.na
\fB\fB-k\fR \fIkdc_list\fR\fR
.ad
.sp .6
.RS 4n
The \fB-k\fR option specifies the KDC host names for the Kerberos client.
\fIkdc_list\fR is a comma-separated list of KDCs. If the \fB-m\fR option is not
used, it is assumed that the first (or only) host in \fIkdc_list\fR is the
master KDC host name. Note that the list specified is used verbatim. This is
helpful when specifying non-fully qualified KDC host names that can be
canonicalized by DNS.
.RE

.sp
.ne 2
.na
\fB\fB-a\fR [ \fIadminuser\fR ]\fR
.ad
.sp .6
.RS 4n
Specifies the Kerberos administrative user.
.RE

.sp
.ne 2
.na
\fB\fB-T\fR \fIkdc_vendor\fR\fR
.ad
.sp .6
.RS 4n
Configure the Kerberos client to associate with a third party server. Valid
\fIkdc_vendor\fR currently supported are:
.sp
.ne 2
.na
\fB\fBms_ad\fR\fR
.ad
.sp .6
.RS 4n
Microsoft Active Directory
.RE

.sp
.ne 2
.na
\fB\fBmit\fR\fR
.ad
.sp .6
.RS 4n
MIT KDC server
.RE

.sp
.ne 2
.na
\fB\fBheimdal\fR\fR
.ad
.sp .6
.RS 4n
Heimdal KDC server
.RE

.sp
.ne 2
.na
\fB\fBshishi\fR\fR
.ad
.sp .6
.RS 4n
Shishi KDC server
.RE

Knowing the administrative password will be required to associate the client
with the server if the \fBms_ad\fR option is specified.
.RE

.sp
.ne 2
.na
\fB\fB-c\fR [ \fIfilepath\fR ]\fR
.ad
.sp .6
.RS 4n
Specifies the pathname to the \fBkrb5.conf\fR(5) master file, to be copied over
to the local host. The path specified normally points to a master copy on a
remote host and brought over to the local host by means of NFS.
.RE

.sp
.ne 2
.na
\fB\fB-d\fR [ \fIdnsarg\fR ]\fR
.ad
.sp .6
.RS 4n
Specifies the DNS lookup option to be used and specified in the
\fBkrb5.conf\fR(5) file. Valid \fIdnsarg\fR entries are: \fBnone\fR,
\fBdns_lookup_kdc\fR, \fBdns_lookup_realm\fR and \fBdns_fallback\fR. Any other
entry is considered invalid. The latter three \fIdnsarg\fR values assume the
same meaning as those described in \fBkrb5.conf\fR. \fBdns_lookup_kdc\fR
implies DNS lookups for the KDC and the other servers. \fBdns_lookup_realm\fR
is for host/domain name-to-realm mapping by means of DNS. \fBdns_fallback\fR is
a superset and does DNS lookups for both the servers and the host/domain
name-to-realm mapping. A lookup option of \fBnone\fR specifies that DNS is not
be used for any kind of mapping lookup.
.RE

.sp
.ne 2
.na
\fB\fB-D\fR \fIdomain_list\fR\fR
.ad
.sp .6
.RS 4n
Specifies the host and/or domain names to be mapped to the Kerberos client's
default realm name. \fIdomain_list\fR is a comma-separated list, for example
"\fBexample.com,host1.example.com\fR". If the \fB-D\fR option is not used, then
only the client's domain is used for this mapping. For example, if the client
is \fBhost1.eng.example.com\fR, then the domain that is mapped to the
\fBEXAMPLE.COM\fR realm is \fBexample.com\fR.
.RE

.sp
.ne 2
.na
\fB\fB-K\fR\fR
.ad
.sp .6
.RS 4n
Configure the Kerberos client without service keys, which are usually stored in
\fB/etc/krb5/krb5.keytab\fR. This is useful in the following scenarios:
.RS +4
.TP
.ie t \(bu
.el o
The client IP address is dynamically assigned and therefore does not host
Kerberized services.
.RE
.RS +4
.TP
.ie t \(bu
.el o
Client has a static IP address, but does not want to host any Kerberized
services.
.RE
.RS +4
.TP
.ie t \(bu
.el o
Client has a static IP address, but the local administrator does not currently
have service keys available for the machine. It is expected that, at a later
time, these keys will be installed on the machine.
.RE
.RE

.sp
.ne 2
.na
\fB\fB-f\fR [ \fIfqdn_list\fR ]\fR
.ad
.sp .6
.RS 4n
This option creates a service principal entry (host/nfs/root) associated with
each of the listed fqdn's, if required, and subsequently adds the entries to
the local host's \fBkeytab\fR.
.sp
\fIfqdn_list\fR is a comma-separated list of one or more fully qualified DNS
domain names.
.sp
This option is especially useful in Kerberos realms having systems offering
kerberized services, but situated in multiple different DNS domains.
.RE

.sp
.ne 2
.na
\fB\fB-h\fR \fIlogical_host_name\fR\fR
.ad
.sp .6
.RS 4n
Specifies that the Kerberos client is a node in a cluster. The
\fIlogical_host_name\fR is the logical host name given to the cluster. The
resulting \fB/etc/krb5/krb5.conf\fR and \fB/etc/krb5/krb5.keytab\fR files must
be manually copied over to the other members of the cluster.
.RE

.sp
.ne 2
.na
\fB\fB-m\fR \fImaster_kdc\fR\fR
.ad
.sp .6
.RS 4n
This option specifies the master KDC to be used by the Kerberos client.
\fImaster_kdc\fR is the host name of the master KDC for the client. If the
\fB-m\fR option is not used, then it is assumed that the first KDC host name
listed with the \fB-k\fR option is the master KDC.
.RE

.sp
.ne 2
.na
\fB\fB-p\fR [ \fIprofile\fR ]\fR
.ad
.sp .6
.RS 4n
Specifies the profile to be used to enable the reading in of the values of all
the parameters required for setup of the machine as a Kerberos client.
.sp
The profile should have entries in the format:
.sp
.in +2
.nf
\fIPARAM\fR \fI<value>\fR
.fi
.in -2
.sp

Valid \fIPARAM\fR entries are: \fBREALM\fR, \fBKDC\fR, \fBADMIN\fR,
\fBFILEPATH\fR, \fBNFS\fR, \fBDNSLOOKUP\fR, \fBFQDN\fR, \fBNOKEY\fR,
\fBNOSOL\fR, \fBLHN\fR, \fBKDCVENDOR\fR, \fBRMAP\fR, \fBMAS\fR, and \fBPAM\fR.
.sp
These profile entries correspond to the \fB-R\fR [\fIrealm\fR], \fB-k\fR
[\fIkdc\fR], \fB-a\fR [\fIadminuser\fR], \fB-c\fR [\fIfilepath\fR], \fB-n\fR,
\fB-d\fR [\fIdnsarg\fR], \fB-f\fR [\fIfqdn_list\fR], \fB-K\fR, \fB-h\fR
[\fIlogical_host_name\fR], \fB-T\fR [\fIkdc_vendor\fR], \fB-D\fR
[\fIdomain_list\fR], \fB-m\fR [\fImaster_kdc\fR], and \fB-s\fR
[\fIpam_service\fR] command-line options, respectively. Any other \fIPARAM\fR
entry is considered invalid and is ignored.
.sp
The NFS profile entry can have a value of 0 (do nothing) or 1 (operation is
requested). Any other value is considered invalid and is ignored.
.sp
Keep in mind that the command line options override the \fIPARAM\fR values
listed in the profile.
.RE

.sp
.ne 2
.na
\fB\fB-s\fR \fIpam_service\fR\fR
.ad
.sp .6
.RS 4n
Specifies that the PAM service names, listed in \fIpam_service\fR, are
authenticated through Kerberos before any other type of authentication. Using
this option updates \fBpam.conf\fR(5) to include \fBpam_krb5\fR(7) to existing
authentication stacks for the specified service(s) in \fIpam_service\fR. An
example of a possible \fIpam_service\fR value is: \fBdtlogin,sshd-kbdint\fR.
.RE

.SH EXAMPLES
\fBExample 1 \fRSetting Up a Kerberos Client Using Command-Line Options
.sp
.LP
To setup a Kerberos client using the \fBclntconfig/admin\fR administrative
principal for realm \fB\&'EXAMPLE.COM', kdc `example1.example.com'\fR and
that also does kerberized NFS, enter:

.sp
.in +2
.nf
# /usr/sbin/kclient -n -R EXAMPLE.COM -k example1.example.com -a clntconfig
.fi
.in -2
.sp

.sp
.LP
Alternatively, to set up a Kerberos client using the \fBclntconfig/admin\fR
administrative principal for the realm \fB`EAST.EXAMPLE.COM', kdc
`example2.east.example.com'\fR and that also needs service principal(s) created
and/or added to the local \fBkeytab\fR for multiple DNS domains, enter:

.sp
.in +2
.nf
# /usr/sbin/kclient -n -R EAST.EXAMPLE.COM -k example2.east.example.com \e
-f west.example.com,central.example.com -a clntconfig
.fi
.in -2

.sp
.LP
Note that the \fBkrb5\fR administrative principal used by the administrator
needs to have only \fBadd\fR, \fBinquire\fR, \fBchange-pwd\fR and \fBmodify\fR
privileges (for the principals in the KDC database) in order for the
\fBkclient\fR utility to run. A sample \fBkadm5.acl\fR(5) entry is:

.sp
.in +2
.nf
clntconfig/admin@EXAMPLE.COM acmi
.fi
.in -2
.sp

.LP
\fBExample 2 \fRSetting Up a Kerberos Client Using the Profile Option
.sp
.LP
To setup a Kerberos client using the \fBclntconfig/admin\fR administrative
principal for realm \fB`EXAMPLE.COM', kdc `example1.example.com'\fR and that
also copies over the master \fBkrb5.conf\fR from a specified location, enter:

.sp
.in +2
.nf
# /usr/sbin/kclient -p /net/example1.example.com/export/profile.krb5
.fi
.in -2
.sp

.sp
.LP
The contents of \fBprofile.krb5\fR:

.sp
.in +2
.nf
REALM EXAMPLE.COM
KDC example1.example.com
ADMIN clntconfig
FILEPATH /net/example1.example.com/export/krb5.conf
NFS 0
DNSLOOKUP none
.fi
.in -2
.sp

.LP
\fBExample 3 \fRSetting Up a Kerberos Client That Has a Dynamic IP Address
.sp
.LP
In this example a Kerberos client is a DHCP client that has a dynamic IP
address. This client does not wish to host any Kerberized services and
therefore does not require a \fBkeytab\fR (\fB/etc/krb5/krb5.keytab\fR) file.

.sp
.LP
For this type of client the administrator would issue the following command to
configure this machine to be a Kerberos client of the \fBEXAMPLE.COM\fR realm
with the KDC server \fBkdc1.example.com\fR:

.sp
.in +2
.nf
# \fB/usr/sbin/kclient -K -R EXAMPLE.COM -k kdc1.example.com\fR
.fi
.in -2
.sp

.SH FILES
.ne 2
.na
\fB\fB/etc/krb5/kadm5.acl\fR\fR
.ad
.sp .6
.RS 4n
Kerberos access control list (ACL) file.
.RE

.sp
.ne 2
.na
\fB\fB/etc/krb5/krb5.conf\fR\fR
.ad
.sp .6
.RS 4n
Default location for the local host's configuration file.
.RE

.sp
.ne 2
.na
\fB\fB/etc/krb5/krb5.keytab\fR\fR
.ad
.sp .6
.RS 4n
Default location for the local host's \fBkeytab\fR file.
.RE

.sp
.ne 2
.na
\fB\fB/etc/nfssec.conf\fR\fR
.ad
.sp .6
.RS 4n
File listing NFS security modes.
.RE

.sp
.ne 2
.na
\fB\fB/etc/resolv.conf\fR\fR
.ad
.sp .6
.RS 4n
DNS resolver configuration file.
.RE

.SH ATTRIBUTES
See \fBattributes\fR(7) for descriptions of the following attributes:
.sp

.sp
.TS
box;
c | c
l | l .
ATTRIBUTE TYPE	ATTRIBUTE VALUE
_
Interface Stability	Committed
.TE

.SH SEE ALSO
.BR encrypt (1),
.BR ksh93 (1),
.BR ldapdelete (1),
.BR ldapmodify (1),
.BR ldapsearch (1),
.BR kadm5.acl (5),
.BR krb5.conf (5),
.BR nfssec.conf (5),
.BR pam.conf (5),
.BR resolv.conf (5),
.BR attributes (7),
.BR pam_krb5 (7),
.BR dd (8),
.BR smbadm (8)
.SH NOTES
\fBfqdn\fR stands for the Fully Qualified Domain Name of the local host. The
\fBkclient\fR utility saves copies of both the \fBkrb5.conf\fR(5) and
\fBnfssec.conf\fR(5) files to files with corresponding names and \fB\&.sav\fR
extensions. The optional copy of the \fBkrb5.conf\fR(5) master file is neither
encrypted nor integrity-protected and it takes place over regular NFS.