kclient(1M) System Administration Commands kclient(1M)NAMEkclient - set up a machine as a Kerberos client
SYNOPSIS
/usr/sbin/kclient [-n] [-R realm] [-k kdc] [-a adminuser]
[-c filepath] [-d dnsarg] [-f fqdn_list] [-h logical_host_name]
[-k kdc_list] [-m master_kdc] [-p profile] [-s pam_service]
[-T kdc_vendor]
DESCRIPTION
By specifying the various command options, you can use the kclient
utility to:
o Configure a machine as a Kerberos client for a specified
realm and for KDC by setting up krb5.conf(4).
o Add the Kerberos host principal to the local host's keytab
file (/etc/krb5/krb5.keytab).
o Set up the machine to do kerberized NFS.
o Bring over a master krb5.conf copy from a specified path‐
name.
o Setup a machine to do server and/or host/domain name-to-
realm mapping lookups by means of DNS.
o Configure a Kerberos client to use an MS Active Directory
server. This generates a keytab file with the Kerberos
client's service keys populated.
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.
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 keytab file.
o Setup a Kerberos client to join an environment that consists
of Kerberos servers that are non-Solaris and non-MS Active
Directory servers.
o Configure pam.conf(4) to use Kerberos authentication for
specified services.
o Configure the client as a simple NTP broadcast/multicast
client.
o Specify custom domain/host name-to-realm name mappings.
o Setup the Kerberos client to use multiple KDC servers.
The kclient 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 (realm and adminuser), if found missing in the non-interactive
run. The interactive mode is invoked when the utility is run without
any command-line arguments.
Both the interactive and non-interactive forms of kclient can add the
host/fqdn entry to the local host's keytab 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 adminuser. The
host/fqdn, nfs/fqdn, and root/fqdn principals can be added to the KDC
database (if not already present) before their possible addition to the
local host's keytab.
The kclient utility assumes that the local host has been setup for DNS
and requires the presence of a valid resolv.conf(4). Also, kclient 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 ntpd man page, delivered in the SUNWntpu package (not a SunOS
man page).
OPTIONS
The non-interactive mode supports the following options:
-n
Set up the machine for kerberized NFS. This involves making changes
to krb5* security flavors in nfssec.conf(4). This option will also
add nfs/fqdn and root/fqdn entries to the local host's keytab file
if the -K option has not been specified.
-R [ realm ]
Specifies the Kerberos realm.
-k kdc_list
The -k option specifies the KDC host names for the Kerberos client.
kdc_list is a comma-separated list of KDCs. If the -m option is not
used, it is assumed that the first (or only) host in kdc_list is
the master KDC host name. Note that the list specified is used ver‐
batim. This is helpful when specifying non-fully qualified KDC host
names that can be canonicalized by DNS.
-a [ adminuser ]
Specifies the Kerberos administrative user.
-T kdc_vendor
Configure the Kerberos client to associate with a third party
server. Valid kdc_vendor currently supported are:
ms_ad
Microsoft Active Directory
mit
MIT KDC server
heimdal
Heimdal KDC server
shishi
Shishi KDC server
Knowing the administrative password will be required to associate
the client with the server if the ms_ad option is specified.
-c [ filepath ]
Specifies the pathname to the krb5.conf(4) 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.
-d [ dnsarg ]
Specifies the DNS lookup option to be used and specified in the
krb5.conf(4) file. Valid dnsarg entries are: none, dns_lookup_kdc,
dns_lookup_realm and dns_fallback. Any other entry is considered
invalid. The latter three dnsarg values assume the same meaning as
those described in krb5.conf. dns_lookup_kdc implies DNS lookups
for the KDC and the other servers. dns_lookup_realm is for
host/domain name-to-realm mapping by means of DNS. dns_fallback is
a superset and does DNS lookups for both the servers and the
host/domain name-to-realm mapping. A lookup option of none speci‐
fies that DNS is not be used for any kind of mapping lookup.
-D domain_list
Specifies the host and/or domain names to be mapped to the Kerberos
client's default realm name. domain_list is a comma-separated list,
for example "example.com,host1.example.com". If the -D option is
not used, then only the client's domain is used for this mapping.
For example, if the client is host1.eng.example.com, then the
domain that is mapped to the EXAMPLE.COM realm is example.com.
-K
Configure the Kerberos client without service keys, which are usu‐
ally stored in /etc/krb5/krb5.keytab. This is useful in the follow‐
ing scenarios:
o The client IP address is dynamically assigned and there‐
fore does not host Kerberized services.
o Client has a static IP address, but does not want to
host any Kerberized services.
o Client has a static IP address, but the local adminis‐
trator 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.
-f [ fqdn_list ]
This option creates a service principal entry (host/nfs/root) asso‐
ciated with each of the listed fqdn's, if required, and subse‐
quently adds the entries to the local host's keytab.
fqdn_list is a comma-separated list of one or more fully qualified
DNS domain names.
This option is especially useful in Kerberos realms having systems
offering kerberized services, but situated in multiple different
DNS domains.
-h logical_host_name
Specifies that the Kerberos client is a node in a cluster. The log‐
ical_host_name is the logical host name given to the cluster. The
resulting /etc/krb5/krb5.conf and /etc/krb5/krb5.keytab files must
be manually copied over to the other members of the cluster.
-m master_kdc
This option specifies the master KDC to be used by the Kerberos
client. master_kdc is the host name of the master KDC for the
client. If the -m option is not used, then it is assumed that the
first KDC host name listed with the -k option is the master KDC.
-p [ profile ]
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.
The profile should have entries in the format:
PARAM <value>
Valid PARAM entries are: REALM, KDC, ADMIN, FILEPATH, NFS,
DNSLOOKUP, FQDN, NOKEY, NOSOL, LHN, KDCVENDOR, RMAP, MAS, and PAM.
These profile entries correspond to the -R [realm], -k [kdc], -a
[adminuser], -c [filepath], -n, -d [dnsarg], -f [fqdn_list], -K, -h
[logical_host_name], -T [kdc_vendor], -D [domain_list], -m [mas‐
ter_kdc], and -s [pam_service] command-line options, respectively.
Any other PARAM entry is considered invalid and is ignored.
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.
Keep in mind that the command line options override the PARAM val‐
ues listed in the profile.
-s pam_service
Specifies that the PAM service names, listed in pam_service, are
authenticated through Kerberos before any other type of authentica‐
tion. Using this option updates pam.conf(4) to include pam_krb5(5)
to existing authentication stacks for the specified service(s) in
pam_service. An example of a possible pam_service value is:
gdm,sshd-kbdint.
EXAMPLES
Example 1 Setting Up a Kerberos Client Using Command-Line Options
To setup a Kerberos client using the clntconfig/admin administrative
principal for realm 'ABC.COM', kdc `example1.com' and that also does
kerberized NFS, enter:
# /usr/sbin/kclient -n -R ABC.COM -k example1.com -a clntconfig
Alternatively, to set up a Kerberos client using the clntconfig/admin
administrative principal for the realm `EAST.ABC.COM', kdc `exam‐
ple2.east.abc.com' and that also needs service principal(s) created
and/or added to the local keytab for multiple DNS domains, enter:
# /usr/sbin/kclient -n -R EAST.ABC.COM -k example2.east.abc.com \
-f west.abc.com,central.abc.com -a clntconfig
Note that the krb5 administrative principal used by the administrator
needs to have only add, inquire, change-pwd and modify privileges (for
the principals in the KDC database) in order for the kclient utility to
run. A sample kadm5.acl(4) entry is:
clntconfig/admin@ABC.COM acmi
Example 2 Setting Up a Kerberos Client Using the Profile Option
To setup a Kerberos client using the clntconfig/admin administrative
principal for realm `ABC.COM', kdc `example1.com' and that also copies
over the master krb5.conf from a specified location, enter:
# /usr/sbin/kclient -p /net/example1.com/export/profile.krb5
The contents of profile.krb5:
REALM ABC.COM
KDC example1
ADMIN clntconfig
FILEPATH /net/example1.com/export/krb5.conf
NFS 0
DNSLOOKUP none
Example 3 Setting Up a Kerberos Client That Has a Dynamic IP Address
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 keytab (/etc/krb5/krb5.keytab) file.
For this type of client the administrator would issue the following
command to configure this machine to be a Kerberos client of the
ABC.COM realm with the KDC server kdc1.example.com:
# /usr/sbin/kclient -K -R EXAMPLE.COM -k kdc1.example.com
FILES
/etc/krb5/kadm5.acl
Kerberos access control list (ACL) file.
/etc/krb5/krb5.conf
Default location for the local host's configuration file.
/etc/krb5/krb5.keytab
Default location for the local host's keytab file.
/etc/nfssec.conf
File listing NFS security modes.
/etc/resolv.conf
DNS resolver configuration file.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌─────────────────────────────┬─────────────────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├─────────────────────────────┼─────────────────────────────┤
│Availability │system/security/kerberos-5 │
├─────────────────────────────┼─────────────────────────────┤
│Interface Stability │Committed │
└─────────────────────────────┴─────────────────────────────┘
SEE ALSOencrypt(1), ksh93(1), ldapdelete(1), ldapmodify(1), ldapsearch(1),
dd(1M), smbadm(1M), kadm5.acl(4), krb5.conf(4), nfssec.conf(4),
pam.conf(4), resolv.conf(4), attributes(5), pam_krb5(5)NOTES
fqdn stands for the Fully Qualified Domain Name of the local host. The
kclient utility saves copies of both the krb5.conf(4) and
nfssec.conf(4) files to files with corresponding names and .sav exten‐
sions. The optional copy of the krb5.conf(4) master file is neither
encrypted nor integrity-protected and it takes place over regular NFS.
SunOS 5.11 22 Oct 2009 kclient(1M)
