How to Install the Kerberos Authentication Service

1. Install Kerberos KDC server and client.

   1. Download and install the krb5 server package.

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      rpm -ivh krb5-server-1.10.3-10.el6_4.6.x86_64.rpm

      Verify that the following rpm packages are installed before configuring KDC:

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      $ rpm -qa | grep -i krb5
      pam_krb5-2.3.11-9.el6.x86_64
      krb5-server-1.10.3-10.el6_4.6.x86_64
      krb5-workstation-1.10.3-10.el6_4.6.x86_64
      krb5-libs-1.10.3-10.el6_4.6.x86_64

   2. Install via yum.

      On the KDC server:

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      yum install krb5-server krb5-libs krb5-auth-dialog

      On the Kerberos client:

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      yum install krb5-workstation krb5-libs krb5-auth-dialog

2. Modify the /etc/krb5.conf file.

   Modify /etc/krb5.conf to look like the code below with the appropriate REALM and DOMAIN_REALM mappings. krb5.conf can be found in /etc by default.

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   [logging]
    default = FILE:/var/log/krb5libs.log
    kdc = FILE:/var/log/krb5kdc.log
    admin_server = FILE:/var/log/kadmind.log
   
   [libdefaults]
    default_realm = MYREALM.COM
    dns_lookup_realm = false
    dns_lookup_kdc = false
    ticket_lifetime = 24h
    renew_lifetime = 7d
    forwardable = true
   
   [realms]
    MYREALM.COM = {
     kdc = elserver1.example.com
     admin_server = elserver1.example.com
    }
   
   [domain_realm]
    .myrealm.com =CTCCDH1.COM
   myrealm.com =CTCCDH1.COM
   

3. Modify the KDC.conf file.

   Log in to the KDC server and modify /var/kerberos/krb5kdc/kdc.conf as follows:

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   [kdcdefaults]
    kdc_ports = 88
    kdc_tcp_ports = 88
   
   [realms]
    MYREALM.COM = {
     #master_key_type = aes256-cts
     acl_file = /var/kerberos/krb5kdc/kadm5.acl
     dict_file = /usr/share/dict/words
     admin_keytab = /var/kerberos/krb5kdc/kadm5.keytab
     supported_enctypes = aes256-cts:normal aes128-cts:normal des3-hmac-sha1:normal arcfour-hmac:normal des-hmac-sha1:normal des-cbc-md5:normal des-cbc-crc:normal
    }
   

4. Assign administrator privileges.

   The users can be granted administrator privileges to the database using the file /var/kerberos/krb5kdc/kadm5.acl.

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   */admin@MYREALM.COM     *

   In the above example, any principal in the MYREALM with an admin instance has all administrator privileges.

5. Create a principal.

   Create the principal using the command addprinc. For example, create a principal with the user name “root”.

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   $ kadmin.local -q "addprinc root/admin"
   Authenticating as principal root/admin@MYREALM.COM with password.
   WARNING: no policy specified for root/admin@MYREALM.COM; defaulting to no policy
   Enter password for principal "root/admin@MYREALM.COM":
   Re-enter password for principal "root/admin@MYREALM.COM":
   Principal "root/admin@MYREALM.COM" created.

6. Create the database.

   The following command creates the principal database in /var/kerberos/krb5kdc.

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   kdb5_util create -r $realm -s

   If the database already exists, it will remove all the related files in /var/kerberos/krb5kdc. By default, the database name is "principal." You can add the -d flag to rename the database.

7. Start the Kerberos Service.

   Start the KDC and kadmin daemons as shown below.

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   # service krb5kdc start
   Starting Kerberos 5 KDC:               [  OK  ]
   
   # service kadmin start
   Starting Kerberos 5 Admin Server:      [  OK  ]