Configuring Kerberos Clients

Kerberos clients include any host, that is not a KDC server, on the network that needs to use Kerberos services. This section provides procedures for installing a Kerberos client, as well as specific information about using root authentication to mount NFS file systems.

Configuring Kerberos Clients (Task Map)

The following task map includes all of the procedures associated with setting up Kerberos clients. Each row includes a task identifier, a description of why you would want to do that task, followed by a link to the task.

How to Create a Kerberos Client Installation Profile

This procedure creates a kclient profile that can be used when you install a Kerberos client. By using the kclient profile, you reduce the likelihood of typing errors. Also, using the profile reduces user intervention as compared to the interactive process.

1. Become superuser.
2. Create a kclient installation profile.

   A sample kclient profile could look similar to the following:

   client# cat /net/denver.example.com/export/install/profile
   REALM EXAMPLE.COM
   KDC kdc1.example.com
   ADMIN clntconfig
   FILEPATH /net/denver.example.com/export/install/krb5.conf
   NFS 1
   DNSLOOKUP none

How to Automatically Configure a Kerberos Client

Before You Begin

This procedure uses an installation profile. See How to Create a Kerberos Client Installation Profile.

To complete this task, you must assume the root role. For more information, see How to Use Your Assigned Administrative Rights.

• Run the kclient installation script.

  You need to provide the password for the clntconfig principal to complete the process.

  client# /usr/sbin/kclient -p /net/denver.example.com/export/install/profile
  
  Starting client setup
  ---------------------------------------------------
  
  kdc1.example.com
  
  Setting up /etc/krb5/krb5.conf.
  
  Obtaining TGT for clntconfig/admin ...
  Password for clntconfig/admin@EXAMPLE.COM: <Type the password>
  
  nfs/client.example.com entry ADDED to KDC database.
  nfs/client.example.com entry ADDED to keytab.
  
  host/client.example.com entry ADDED to KDC database.
  host/client.example.com entry ADDED to keytab.
  
  Copied /net/denver.example.com/export/install/krb5.conf.
  
  ---------------------------------------------------
  Setup COMPLETE.
  
  client#

Example 21-8 Automatically Configuring a Kerberos Client With Command-Line Overrides

The following example overrides the DNSARG and the KDC parameters that are set in the installation profile.

# /usr/sbin/kclient -p /net/denver.example.com/export/install/profile\
-d dns_fallback -k kdc2.example.com

Starting client setup
---------------------------------------------------

kdc1.example.com

Setting up /etc/krb5/krb5.conf.

Obtaining TGT for clntconfig/admin ...
Password for clntconfig/admin@EXAMPLE.COM: <Type the password>

nfs/client.example.com entry ADDED to KDC database.
nfs/client.example.com entry ADDED to keytab.

host/client.example.com entry ADDED to KDC database.
host/client.example.com entry ADDED to keytab.

Copied /net/denver.example.com/export/install/krb5.conf.

---------------------------------------------------
Setup COMPLETE.

client#

How to Interactively Configure a Kerberos Client

This procedure uses the kclient installation utility without a installation profile. In the Oracle Solaris 11 release, the kclient utility improved ease of use and the ability to work with Active Directory servers. See How to Configure a Kerberos Client for an Active Directory Server for more information. See Example 21-10 for an example of running kclient on a previous release.

Before You Begin

To complete this task, you must assume the root role. For more information, see How to Use Your Assigned Administrative Rights.

• Run the kclient installation script.

  You need to provide the following information:

  • Kerberos realm name

  • KDC master host name

  • KDC slave host names

  • Domains to map to the local realm

  • PAM service names and options to use for Kerberos authentication

  1. Indicate if the KDC server is not running an Oracle Solaris release.

     If this system is a client of a KDC server that is not running an Oracle Solaris release, you need to define the type of server that is running the KDC. The available servers are: Microsoft Active Directory, MIT KDC server, Heimdal KDC server, and Shishi KDC server.

  2. Select if DNS should be used for Kerberos lookups.

     If you use DNS for Kerberos lookups, you need to enter the DNS lookup option that you want to use. Valid options are dns_lookup_kdc, dns_lookup_realm, and dns_fallback. See the krb5.conf(4) man page for more information about these values.

  3. Define the name of the Kerberos realm and the master KDC hostname.

     This information is added to the /etc/krb5/krb5.conf configuration file.

  4. Select if slave KDCs exist.

     If there are slave KDCs in the realm, then you need to enter the slave KDC host names. This information is used to create additional KDC entries in the client's configuration file.

  5. Indicate if service or host keys are required.

     Normally, service or host keys are not required unless the client system is hosting Kerberized services.

  6. Specify if the client is a member of a cluster.

     If the client is a member of a cluster, then you need to provide the logical name of the cluster. The logical host name is used when creating service keys, which is required when hosting Kerberos services from clusters.

  7. Identify any domains or hosts to map to the current realm.

     This mapping allows other domains to belong in the default realm of the client.

  8. Specify if the client will use Kerberized NFS.

     NFS service keys need to be created if the client will host NFS services using Kerberos.

  9. Indicate if a new PAM policy needs to be created.

     This allows you to set which PAM services use Kerberos for authentication. You need to enter the service name and a flag indicating how Kerberos authentication is to be used. The valid flag options are:

     • first – use Kerberos authentication first, and only use UNIX if Kerberos authentication fails

     • only – use Kerberos authentication only

     • optional – use Kerberos authentication optionally

  10. Select if the master /etc/krb5/krb5.conf file should be copied.

      This option allows for specific configuration information to be used when the arguments to kclient are not sufficient.

Example 21-9 Running the kclient Installation Utility

client# /usr/sbin/kclient

Starting client setup
---------------------------------------------------

Is this a client of a non-Solaris KDC ? [y/n]: n
        No action performed.
Do you want to use DNS for kerberos lookups ? [y/n]: n
        No action performed.
Enter the Kerberos realm: EXAMPLE.COM
Specify the KDC hostname for the above realm: kdc1.example.com

Note, this system and the KDC's time must be within 5 minutes of each other for
Kerberos to function. Both systems should run some form of time synchronization
system like Network Time Protocol (NTP).
Do you have any slave KDC(s) ? [y/n]: y
Enter a comma-separated list of slave KDC host names: kdc2.example.com

Will this client need service keys ? [y/n]: n
        No action performed.
Is this client a member of a cluster that uses a logical host name ? [y/n]: n
        No action performed.
Do you have multiple domains/hosts to map to realm ? [y/n]: y
Enter a comma-separated list of domain/hosts to map to the default realm: engineering.example.com, \
        example.com

Setting up /etc/krb5/krb5.conf.

Do you plan on doing Kerberized nfs ? [y/n]: y
Do you want to update /etc/pam.conf ? [y/n]: y
Enter a comma-separated list of PAM service names in the following format:
service:{first|only|optional}: xscreensaver:first
Configuring /etc/pam.conf.

Do you want to copy over the master krb5.conf file ? [y/n]: n
        No action performed.

---------------------------------------------------
Setup COMPLETE.

Example 21-10 Running the kclient Installation Utility in the Oracle Solaris 10 Release

The following output shows the results of running the kclient command.

client# /usr/sbin/kclient

Starting client setup
---------------------------------------------------

Do you want to use DNS for kerberos lookups ? [y/n]: n
        No action performed.
Enter the Kerberos realm: EXAMPLE.COM
Specify the KDC hostname for the above realm: kdc1.example.com

Setting up /etc/krb5/krb5.conf.

Enter the krb5 administrative principal to be used: clntconfig/admin
Obtaining TGT for clntconfig/admin ...
Password for clntconfig/admin@EXAMPLE.COM: <Type the password>
Do you plan on doing Kerberized nfs ? [y/n]: n

host/client.example.com entry ADDED to KDC database.
host/client.example.com entry ADDED to keytab.

Do you want to copy over the master krb5.conf file ? [y/n]: y
Enter the pathname of the file to be copied: \
/net/denver.example.com/export/install/krb5.conf

Copied /net/denver.example.com/export/install/krb5.conf.

---------------------------------------------------
Setup COMPLETE !
#

How to Configure a Kerberos Client for an Active Directory Server

This procedure uses the kclient installation utility without a installation profile.

Before You Begin

You must assume the root role. For more information, see How to Use Your Assigned Administrative Rights.

1. (Optional) Enable DNS resource record creation for the client.

   client# sharectl set -p ddns_enable=true smb

2. Run the kclient utility.

   The -T option selects a KDC server type. In this case an Active Directory server is selected.

   client# kclient -T ms_ad

   By default, you will need to provide the password for the Administrator principal.

Example 21-11 Configuring a Kerberos Client for an Active Directory Server Using kclient

The following output shows the results of running the kclient command using the ms_ad (Microsoft Active Directory) server type argument. The client will be joined to the Active Directory domain called EXAMPLE.COM.

client# /usr/sbin/kclient -T ms_ad

Starting client setup
---------------------------------------------------

Attempting to join 'CLIENT' to the 'EXAMPLE.COM' domain.
Password for Administrator@EXAMPLE.COM: <Type the password>
Forest name found: example.com
Looking for local KDCs, DCs and global catalog servers (SVR RRs).

Setting up /etc/krb5/krb5.conf

Creating the machine account in AD via LDAP.
---------------------------------------------------
Setup COMPLETE.
#

How to Manually Configure a Kerberos Client

In this procedure, the following configuration parameters are used:

• Realm name = EXAMPLE.COM

• DNS domain name = example.com

• Master KDC = kdc1.example.com

• Slave KDC = kdc2.example.com

• NFS server = denver.example.com

• Client = client.example.com

• admin principal = kws/admin

• User principal = mre

• Online help URL = http://docs.oracle.com/cd/E23824_01/html/821-1456/aadmin-23.html

  ---

  Note - Adjust the URL to point to the section, as described in Online Help URL in the Graphical Kerberos Administration Tool.

  ---

Before You Begin

You must assume the root role. For more information, see How to Use Your Assigned Administrative Rights.

1. Edit the Kerberos configuration file (krb5.conf).

   To change the file from the Kerberos default version, you need to change the realm names and the server names. You also need to identify the path to the help files for gkadmin.

   kdc1 # cat /etc/krb5/krb5.conf
   [libdefaults]
           default_realm = EXAMPLE.COM
   
   [realms]
           EXAMPLE.COM = {
           kdc = kdc1.example.com
           kdc = kdc2.example.com
           admin_server = kdc1.example.com
           }
   
   [domain_realm]
           .example.com = EXAMPLE.COM
   #
   # if the domain name and realm name are equivalent, 
   # this entry is not needed
   #
   [logging]
           default = FILE:/var/krb5/kdc.log
           kdc = FILE:/var/krb5/kdc.log
   
   [appdefaults]
       gkadmin = {
           help_url = http://docs.oracle.com/cd/E23824_01/html/821-1456/aadmin-23.html

   ---

   Note - If you want to restrict the encryption types, you can set the default_tkt_enctypes or default_tgs_enctypes lines. Refer to Using Kerberos Encryption Types for a description of the issues involved with restricting the encryption types.

   ---

2. (Optional) Change the process that is used to locate the KDCs.

   By default, the Kerberos realm to KDC mapping is determined in the following order:

   • The definition in the realms section in krb5.conf

   • By looking up SRV records in DNS.

   You can change this behavior by adding dns_lookup_kdc or dns_fallback to the libdefaults section of the krb5.conf file. See the krb5.conf(4) man page for more information. Note that referrals are always tried first.

3. (Optional) Change the process used to determine the realm for a host.

   By default the host to realm mapping is determined in the following order:

   • If the KDC supports referrals, then the KDC may inform the client which realm the host belongs to.

   • By the definition of domain_realm in the krb5.conf file.

   • The DNS domainname of the host.

   • The default realm.

   You can change this behavior by adding dns_lookup_kdc or dns_fallback to the libdefaults section of the krb5.conffile. See the krb5.conf(4) man page for more information. Note that referrals will always be tried first.

4. (Optional) Synchronize the client's clock with the master KDC's clock by using NTP or another clock synchronization mechanism.

   Installing and using the Network Time Protocol (NTP) is not required. However, every clock must be synchronized with the time on the KDC server within a maximum difference defined in the clockskew relation in the krb5.conf file for authentication to succeed. See Synchronizing Clocks Between KDCs and Kerberos Clients for information about NTP.

5. Start kadmin.

   You can use the Graphical Kerberos Administration Tool to add a principal, as explained in How to Create a New Kerberos Principal. To do so, you must log in with one of the admin principal names that you created when you configured the master KDC. However, the following example shows how to add the required principals by using the command line.

   denver # /usr/sbin/kadmin -p kws/admin
   Enter password: <Type kws/admin password>
   kadmin: 

   1. (Optional) Create a user principal if a user principal does not already exist.

      You need to create a user principal only if the user associated with this host does not already have a principal assigned to him or her.

      kadmin: addprinc mre
      Enter password for principal mre@EXAMPLE.COM: <Type the password>
      Re-enter password for principal mre@EXAMPLE.COM: <Type it again>
      kadmin: 

   2. (Optional) Create a root principal and add the principal to the server's keytab file.

      This step is required so that the client can have root access to file systems mounted using the NFS service. This step is also required if non-interactive root access is needed, such as running cron jobs as root.

      If the client does not require root access to a remote file system which is mounted using the NFS service, then you can skip this step. The root principal should be a two component principal with the second component the host name of the Kerberos client system to avoid the creation of a realm wide root principal. Note that when the principal instance is a host name, the FQDN must be specified in lowercase letters, regardless of the case of the domain name in the name service.

      kadmin: addprinc -randkey root/client.example.com
      Principal "root/client.example.com" created.
      kadmin: ktadd root/client.example.com
      Entry for principal root/client.example.com with kvno 3, encryption type AES-256 CTS mode
                with 96-bit SHA-1 HMAC added to keytab WRFILE:/etc/krb5/krb5.keytab.
      Entry for principal root/client.example.com with kvno 3, encryption type AES-128 CTS mode
                with 96-bit SHA-1 HMAC added to keytab WRFILE:/etc/krb5/krb5.keytab.
      Entry for principal root/client.example.com with kvno 3, encryption type Triple DES cbc
                mode with HMAC/sha1 added to keytab WRFILE:/etc/krb5/krb5.keytab.
      Entry for principal root/client.example.com with kvno 3, encryption type ArcFour
                with HMAC/md5 added to keytab WRFILE:/etc/krb5/krb5.keytab.
      Entry for principal root/client.example.com with kvno 3, encryption type DES cbc mode
                with RSA-MD5 added to keytab WRFILE:/etc/krb5/krb5.keytab.
      kadmin: 

   3. Create a host principal and add the principal to the server's keytab file.

      The host principal is used by remote access services to provide authentication. The principal allows root to acquire a credential, if there is not one already in the keytab file.

      kadmin: addprinc -randkey host/denver.example.com
      Principal "host/denver.example.com@EXAMPLE.COM" created.
      kadmin: ktadd host/denver.example.com
      Entry for principal host/denver.example.com with kvno 3, encryption type AES-256 CTS mode
                with 96-bit SHA-1 HMAC added to keytab WRFILE:/etc/krb5/krb5.keytab.
      Entry for principal host/denver.example.com with kvno 3, encryption type AES-128 CTS mode
                with 96-bit SHA-1 HMAC added to keytab WRFILE:/etc/krb5/krb5.keytab.
      Entry for principal host/denver.example.com with kvno 3, encryption type Triple DES cbc
                mode with HMAC/sha1 added to keytab WRFILE:/etc/krb5/krb5.keytab.
      Entry for principal host/denver.example.com with kvno 3, encryption type ArcFour
                with HMAC/md5 added to keytab WRFILE:/etc/krb5/krb5.keytab.
      Entry for principal host/denver.example.com with kvno 3, encryption type DES cbc mode
                with RSA-MD5 added to keytab WRFILE:/etc/krb5/krb5.keytab.
      kadmin:

   4. (Optional) Add the server's NFS service principal to the server's keytab file.

      This step is only required if the client needs to access NFS file systems using Kerberos authentication.

      kadmin: ktadd nfs/denver.example.com
      Entry for principal nfs/denver.example.com with kvno 3, encryption type AES-256 CTS mode
                with 96-bit SHA-1 HMAC added to keytab WRFILE:/etc/krb5/krb5.keytab.
      Entry for principal nfs/denver.example.com with kvno 3, encryption type AES-128 CTS mode
                with 96-bit SHA-1 HMAC added to keytab WRFILE:/etc/krb5/krb5.keytab.
      Entry for principal nfs/denver.example.com with kvno 3, encryption type Triple DES cbc
                mode with HMAC/sha1 added to keytab WRFILE:/etc/krb5/krb5.keytab.
      Entry for principal nfs/denver.example.com with kvno 3, encryption type ArcFour
                with HMAC/md5 added to keytab WRFILE:/etc/krb5/krb5.keytab.
      Entry for principal nfs/denver.example.com with kvno 3, encryption type DES cbc mode
                with RSA-MD5 added to keytab WRFILE:/etc/krb5/krb5.keytab.
      kadmin: 

   5. Quit kadmin.

      kadmin: quit

6. (Optional) Enable Kerberos with NFS.
   1. Enable Kerberos security modes in the /etc/nfssec.conf file.

      Edit the /etc/nfssec.conf file and remove the “#” that is placed in front of the Kerberos security modes.

      # cat /etc/nfssec.conf
       .
       .
      #
      # Uncomment the following lines to use Kerberos V5 with NFS
      #
      krb5            390003  kerberos_v5     default -               # RPCSEC_GSS
      krb5i           390004  kerberos_v5     default integrity       # RPCSEC_GSS
      krb5p           390005  kerberos_v5     default privacy         # RPCSEC_GSS

   2. Enable DNS.

      If the svc:/network/dns/client:default service is not enabled, enable it. See the resolv.conf(4) man page for more information.

   3. Restart the gssd service.

      # svcadm restart network/rpc/gss

7. If you want the client to automatically renew the TGT or to warn users about Kerberos ticket expiration, create an entry in the /etc/krb5/warn.conf file.

   See the warn.conf(4) man page for more information.

Example 21-12 Setting Up a Kerberos Client Using a Non-Solaris KDC

A Kerberos client can be set up to work with a non-Solaris KDC. In this case, a line must be included in the /etc/krb5/krb5.conf file in the realms section. This line changes the protocol that is used when the client is communicating with the Kerberos password-changing server. The format of this line follows.

[realms]
                EXAMPLE.COM = {
                kdc = kdc1.example.com
                kdc = kdc2.example.com
                admin_server = kdc1.example.com
                kpasswd_protocol = SET_CHANGE
        }

Example 21-13 DNS TXT Records for the Mapping of Host and Domain Name to Kerberos Realm

@ IN SOA kdc1.example.com root.kdc1.example.com (
                                1989020501   ;serial
                                10800        ;refresh
                                3600         ;retry
                                3600000      ;expire
                                86400 )      ;minimum

                        IN      NS      kdc1.example.com.
kdc1                    IN      A       192.146.86.20
kdc2                    IN      A       192.146.86.21

_kerberos.example.com.             IN      TXT     "EXAMPLE.COM"
_kerberos.kdc1.example.com.        IN      TXT     "EXAMPLE.COM"
_kerberos.kdc2.example.com.        IN      TXT     "EXAMPLE.COM"

Example 21-14 DNS SRV Records for Kerberos Server Locations

This example defines the records for the location of the KDCs, the admin server, and the kpasswd server, respectively.

@ IN SOA kdc1.example.com root.kdc1.example.com (
                                1989020501   ;serial
                                10800        ;refresh
                                3600         ;retry
                                3600000      ;expire
                                86400 )      ;minimum

                                   IN      NS      kdc1.example.com.
kdc1                               IN      A       192.146.86.20
kdc2                               IN      A       192.146.86.21

_kerberos._udp.EXAMPLE.COM         IN      SRV 0 0 88  kdc2.example.com
_kerberos._tcp.EXAMPLE.COM         IN      SRV 0 0 88  kdc2.example.com
_kerberos._udp.EXAMPLE.COM         IN      SRV 1 0 88  kdc1.example.com
_kerberos._tcp.EXAMPLE.COM         IN      SRV 1 0 88  kdc1.example.com
_kerberos-adm._tcp.EXAMPLE.COM     IN      SRV 0 0 749 kdc1.example.com
_kpasswd._udp.EXAMPLE.COM          IN      SRV 0 0 749 kdc1.example.com

Example 21-15 Configuring a Solaris Client to Work with a Multiple Master KDC

The Microsoft Active Directory Kerberos service, provides a KDC that runs on multiple masters. In order for a Solaris Client to be able to update information either the admin_server or the kpasswd_server declaration in /etc/krb5/krb5.conf needs to be updated to list all of the servers. This example shows how to allow the client to update information on the KDC shared between kdc1 and kdc2.

[realms]
                EXAMPLE.COM = {
                kdc = kdc1.example.com
                kdc = kdc2.example.com
                admin_server = kdc1.example.com
                admin_server = kdc2.example.com
                }

How to Disable Verification of the Ticket-Granting Ticket

This procedure disables the security check that checks that the KDC of the host principal stored in the local /etc/krb5/krb5.keytab file is the same KDC that issued the ticket-granting ticket (TGT). This check prevents DNS spoofing attacks. However, for some client configurations, the host principal may not be available, so this check would need to be disabled to allow the client to function. These are the configurations that require that this check is disabled:

• The client IP address is dynamically assigned. For instance, a DHCP client.

• The client is not configured to host any services, so no host principal was created.

• The host key is not stored on the client.

Before You Begin

You must assume the root role. For more information, see How to Use Your Assigned Administrative Rights.

• Change the krb5.conf file.

  If the verify_ap_req_nofail option is set to false, the TGT verification process is not enabled. See the krb5.conf(4) man page for more information about this option.

  client # cat /etc/krb5/krb5.conf
  [libdefaults]
          default_realm = EXAMPLE.COM
          verify_ap_req_nofail = false
    ...

  ---

  Note - The verify_ap_req_nofail option can be entered in either the [libdefaults] or the [realms] section of the krb5.conf file. If the option is in the [libdefaults]section, the setting is used for all realms. If the option is in the [realms]section, the setting only applies to the defined realm.

  ---

How to Access a Kerberos Protected NFS File System as the root User

This procedure allows a client to access a NFS file system that requires Kerberos authentication with the root ID privilege. In particular, when the NFS file system is shared with options like: -o sec=krb5,root=client1.sun.com.

• Start kadmin.

  You can use the GUI Kerberos Administration Tool to add a principal, as explained in How to Create a New Kerberos Principal. To do so, you must log in with one of the admin principal names that you created when you configured the master KDC. However, the following example shows how to add the required principals by using the command line.

  denver # /usr/sbin/kadmin -p kws/admin
  Enter password: <Type kws/admin password>
  kadmin: 

  1. Create a root principal for the NFS client.

     This principal is used to provide root equivalent access to NFS mounted file systems that require Kerberos authentication. The root principal should be a two component principal with the second component the host name of the Kerberos client system to avoid the creation of a realm wide root principal. Note that when the principal instance is a host name, the FQDN must be specified in lowercase letters, regardless of the case of the domain name in the name service.

     kadmin: addprinc -randkey root/client.example.com
     Principal "root/client.example.com" created.
     kadmin:

  2. Add the root principal to the server's keytab file.

     This step is required if you added a root principal so that the client can have root access to file systems mounted using the NFS service. This step is also required if non-interactive root access is needed, such as running cron jobs as root.

     kadmin: ktadd root/client.example.com
     Entry for principal root/client.example.com with kvno 3, encryption type AES-256 CTS mode
               with 96-bit SHA-1 HMAC added to keytab WRFILE:/etc/krb5/krb5.keytab.
     Entry for principal root/client.example.com with kvno 3, encryption type AES-128 CTS mode
               with 96-bit SHA-1 HMAC added to keytab WRFILE:/etc/krb5/krb5.keytab.
     Entry for principal root/client.example.com with kvno 3, encryption type Triple DES cbc
               mode with HMAC/sha1 added to keytab WRFILE:/etc/krb5/krb5.keytab.
     Entry for principal root/client.example.com with kvno 3, encryption type ArcFour
               with HMAC/md5 added to keytab WRFILE:/etc/krb5/krb5.keytab.
     Entry for principal root/client.example.com with kvno 3, encryption type DES cbc mode
               with RSA-MD5 added to keytab WRFILE:/etc/krb5/krb5.keytab.
     kadmin: 

  3. Quit kadmin.

     kadmin: quit

How to Configure Automatic Migration of Users in a Kerberos Realm

Users, who do not have a Kerberos principal, can be automatically migrated to an existing Kerberos realm. The migration is achieved by using the PAM framework for the service in use by stacking the pam_krb5_migrate module in the service's authentication stack in the PAM configuration files.

In this example, the gdm and other PAM service names are configured to use the automatic migration. The following configuration parameters are used:

• Realm name = EXAMPLE.COM

• Master KDC = kdc1.example.com

• Machine hosting the migration service = server1.example.com

• Migration service principal = host/server1.example.com

Before You Begin

Set up server1 as a Kerberos client of the realm EXAMPLE.COM. See Configuring Kerberos Clients for more information.

You must assume the root role. For more information, see How to Use Your Assigned Administrative Rights.

1. Check to see if a host service principal for server1 exists.

   The host service principal in the keytab file of server1 is used to authenticate the server to the master KDC.

   server1 # klist -k
   Keytab name: FILE:/etc/krb5/krb5.keytab
       KVNO Principal
       ---- ------------------------------------------------
          3 host/server1.example.com@EXAMPLE.COM
          3 host/server1.example.com@EXAMPLE.COM
          3 host/server1.example.com@EXAMPLE.COM
          3 host/server1.example.com@EXAMPLE.COM

2. Make changes to the PAM configuration file.
   1. Update entries for the gdm service.

      # cat /etc/pam.d/gdm
       .
       .
      
      auth definitive         pam_user_policy.so.1
      auth requisite          pam_authtok_get.so.1
      auth required           pam_dhkeys.so.1
      auth sufficient         pam_krb5.so.1
      auth requisite          pam_unix_auth.so.1
      auth required           pam_unix_cred.so.1
      auth optional           pam_krb5_migrate.so.1

   2. (Optional) Force an immediate password change, if needed.

      The newly created Kerberos accounts can have their password expiration time set to the current time (now), in order to force an immediate Kerberos password change. To set the expiration time to now, add the expire_pw option to the lines that use the pam_krb5_migrate module. See the pam_krb5_migrate(5) man page for more information.

      # cat /etc/pam.d/gdm
       .
       .
      auth optional           pam_krb5_migrate.so.1 expire_pw

   3. Add the pam_krb5 module to the account stack.

      This addition allows for password expiration in Kerberos to block access.

      # cat /etc/pam.d/other
       .
       .
      #
      # Default definition for Account management
      # Used when service name is not explicitly mentioned for account management
      #
      account requisite       pam_roles.so.1
      account definitive      pam_user_policy.so.1
      account required        pam_krb5.so.1
      account required        pam_unix_account.so.1
      account required        pam_tsol_account.so.1
      #

   4. Add the pam_krb5 module to the password stack.

      This addition allows for passwords to be updated when the password expire.

      # cat /etc/pam.d/other
       .
       .
      #
      # Default definition for Password management
      #
      password include        pam_authtok_common
      password sufficient     pam_krb5.so.1
      password required       pam_authtok_store.so.1

3. On the master KDC, update the access control file.

   The following entries grant migrate and inquire privileges to the host/server1.example.com service principal for all users, excepting the root user. It is important that users who should not be migrated are listed in the kadm5.acl file using the U privilege. These entries need to be before the permit all or ui entry. See the kadm5.acl(4) man page for more information.

   kdc1 # cat /etc/krb5/kadm5.acl
   host/server1.example.com@EXAMPLE.COM U root
   host/server1.example.com@EXAMPLE.COM ui *
   */admin@EXAMPLE.COM *

4. On the master KDC, restart the Kerberos administration daemon.

   This step allows the kadmind daemon to use the new kadm5.acl entries.

   kdc1 # svcadm restart network/security/kadmin

5. On the master KDC, add entries to the pam.conf file.

   The following entries enable the kadmind daemon to use the k5migrate PAM service, to validate UNIX user password for accounts that require migration.

   # grep k5migrate /etc/pam.conf
   k5migrate        auth    required        pam_unix_auth.so.1
   k5migrate        account required        pam_unix_account.so.1

How to Configure Account Lockout

• Start kadmin.

  % /usr/sbin/kadmin -p kws/admin
  Enter password: <Type kws/admin password>
  kadmin: 

  1. Create a policy with account lockout parameters.

     In the following example, the add_policy subcommand command is used to create a policy named default. Three authentication failures, during a span of 300 seconds will trigger an account lockout of 900 seconds.

     kadmin: add_policy -maxfailure 3 -failurecountinterval "300 seconds"\
     -lockoutduration "900 seconds" default

  2. Quit kadmin.

     kadmin: quit

Example 21-16 Unlocking a Locked Out Principal

In the following example, a user principal is unlocked:

 /usr/sbin/kadmin -p kws/admin
Enter password: <Type kws/admin password>
kadmin: modify_principal -unlock principal

How to Automatically Renew All Ticket-Granting Tickets (TGTs)

Before You Begin

You must assume the root role. For more information, see How to Use Your Assigned Administrative Rights.

1. Edit the warnd configuration file.

   Add an entry like the following to renew the TGT 30 minutes before the ticket expires and log the message on the users terminal when the renewal succeeds or fails:

   # cat /etc/krb5/warn.conf
   * renew:log terminal 30m

2. Restart the service.

   # svcadm restart network/security/ktkt_warn

Example 21-17 Configuring TGT Expiration Messages on a Server

The following example shows several ways to configure the renewal and message system for TGTs.

# cat /etc/krb5/warn.conf
#
# renew the TGT 30 minutes before expiration and send message to users terminal
#
gtb@EXAMPLE.COM renew:log terminal 30m
#
# send a warning message to a specific email address 20 minutes before TGT expiration
#
mre@EXAMPLE.COM mail 20m mre@example2.com
#
# renew the TGT 20 minutes before expiration and send an email message on failure
#
bricker@EXAMPLE.COM renew:log-failure mail 20m &
#
# catch-all: any principal not matched above will get an email warning
* mail 20m & 

Example 21-18 Configuring TGT Expiration Messages for a User

In addition to configuring an entry for each user at the system level, each user can configure an individual warnd configuration file, which is named /var/user/$USER/krb-warn.conf. For example:

% cat /var/user/gtb/krb-warn.conf
gtb@EXAMPLE.COM renew:log mail 30m &