Creating a keytab file

If you have already created a keytab file for Single Sign-On authentication, you can use this file to configure Kerberos authentication on the proxy server.

You can use the same user account for authentication on all nodes of a cluster. To do so, you must create a keytab file containing the service principal name (SPN) for each of these nodes. When creating a keytab file, you must use the attribute to generate a salt (hash function modifier).

The generated salt must be saved using a method of your choosing to subsequently add new SPNs to the keytab file.

You can also create a separate Active Directory user account for each cluster node for which you want to configure Kerberos authentication.

The keytab file is created on the domain controller server or on a Windows Server computer that is part of the domain, under a domain administrator account.

To create a keytab file using a single user account:

1. In the Active Directory Users and Computers snap-in, create a user account named, for example, control-user.
2. To use the AES256-SHA1 encryption algorithm, do the following in the Active Directory Users and Computers snap-in:
   1. Open the properties of the created account.
   2. On the Account tab, select the This account supports Kerberos AES 256 bit encryption check box.
3. Create a keytab file for control-user using the ktpass utility. To do so, run the following command in the command line:

   C:\Windows\system32\ktpass.exe -princ HTTP/<fully qualified domain name (FQDN) of the Control node>@<realm uppercase Active Directory domain name> -mapuser control-user@<realm uppercase Active Directory domain name> -crypto AES256-SHA1 -ptype KRB5_NT_PRINCIPAL -pass * +dumpsalt -out <path to file>\<file name>.keytab

   The utility will prompt you for the control-user password when running the command.

   The SPN of the node with role Control will be added to the created keytab file. The generated salt is displayed: Hashing password with salt "<hash value>".

4. For each node of the cluster, add an SPN entry to the keytab file. To do so, run the following command:

   C:\Windows\system32\ktpass.exe -princ HTTP/<fully qualified domain name (FQDN) of the node>@<realm uppercase Active Directory domain name> -mapuser control-user@<realm uppercase Active Directory domain name> -crypto AES256-SHA1 -ptype KRB5_NT_PRINCIPAL -pass * -in <path and name of the previously created file>.keytab -out <path and new name>.keytab -setupn -setpass -rawsalt "<hash value of the salt obtained when creating the keytab file at step 3>"

   The utility will prompt you for the control-user password when running the command.

The keytab file will be created. This file will contain all added SPNs of cluster nodes.

Example: For example, you need to create a keytab file that contains SPNs of 3 nodes: control-01.test.local, secondary-01.test.local, and secondary-02.test.local. To create a file named filename1.keytab containing the SPN of the Control node in the C:\keytabs\ folder, you must run the following command: C:\Windows\system32\ktpass.exe -princ HTTP/control-01.test.local@TEST.LOCAL -mapuser control-user@TEST.LOCAL -crypto AES256-SHA1 -ptype KRB5_NT_PRINCIPAL -pass * +dumpsalt -out C:\keytabs\filename1.keytab Suppose you got the salt "TEST.LOCALHTTPcontrol-01.test.local". To add one more SPN, you must run the following command: C:\Windows\system32\ktpass.exe -princ HTTP/secondary-01.test.local@TEST.LOCAL -mapuser control-user@TEST.LOCAL -crypto AES256-SHA1 -ptype KRB5_NT_PRINCIPAL -pass * -in C:\keytabs\filename1.keytab -out C:\keytabs\filename2.keytab -setupn -setpass -rawsalt "TEST.LOCALHTTPcontrol-01.test.local" To add a third SPN, you must run the following command: C:\Windows\system32\ktpass.exe -princ HTTP/secondary-02.test.local@TEST.LOCAL -mapuser control-user@TEST.LOCAL -crypto AES256-SHA1 -ptype KRB5_NT_PRINCIPAL -pass * -in C:\keytabs\filename2.keytab -out C:\keytabs\filename3.keytab -setupn -setpass -rawsalt "TEST.LOCALHTTPcontrol-01.test.local" This will result in the creation of a file named filename3.keytab containing all three added SPNs.

To create a keytab file using a separate user account for each node:

1. In the Active Directory Users and Computers snap-in, create a separate user account for each cluster node (for example, user accounts with names control-user, secondary1-user, secondary2-user and so on).
2. If you want to use the AES256-SHA1 encryption algorithm, do the following in the Active Directory Users and Computers snap-in:
   1. Open the properties of the created account.
   2. On the Account tab, select the This account supports Kerberos AES 256 bit encryption check box.
3. Create a keytab file for control-user using the ktpass utility. To do so, run the following command in the command line:

   C:\Windows\system32\ktpass.exe -princ HTTP/<fully qualified domain name (FQDN) of the Control node>@<realm uppercase Active Directory domain name> -mapuser control-user@<realm uppercase Active Directory domain name> -crypto AES256-SHA1 -ptype KRB5_NT_PRINCIPAL -pass * -out <path to file>\<file name>.keytab

   The utility will prompt you for the control-user password when running the command.

   The SPN of the node with role Control will be added to the created keytab file.

4. For each node of the cluster, add an SPN entry to the keytab file. To do so, run the following command:

   C:\Windows\system32\ktpass.exe -princ HTTP/<fully qualified domain name (FQDN) of the node>@<realm uppercase Active Directory domain name> -mapuser secondary1-user@<realm uppercase Active Directory domain name> -crypto AES256-SHA1 -ptype KRB5_NT_PRINCIPAL -pass * -in <path and name of the previously created file>.keytab -out <path and new name>.keytab

   The utility will prompt you for the secondary1-user password when running the command.

The keytab file will be created. This file will contain all added SPNs of cluster nodes.

Example: For example, you need to create a keytab file that contains SPNs of 3 nodes: control-01.test.local, secondary-01.test.local, and secondary-02.test.local. To create a file named filename1.keytab containing the SPN of the Control node in the C:\keytabs\ folder, you must run the following command: C:\Windows\system32\ktpass.exe -princ HTTP/control-01.test.local@TEST.LOCAL -mapuser control-user@TEST.LOCAL -crypto AES256-SHA1 -ptype KRB5_NT_PRINCIPAL -pass * -out C:\keytabs\filename1.keytab To add one more SPN, you must run the following command: C:\Windows\system32\ktpass.exe -princ HTTP/secondary-01.test.local@TEST.LOCAL -mapuser secondary1-user@TEST.LOCAL -crypto AES256-SHA1 -ptype KRB5_NT_PRINCIPAL -pass * -in C:\keytabs\filename1.keytab -out C:\keytabs\filename2.keytab To add a third SPN, you must run the following command: C:\Windows\system32\ktpass.exe -princ HTTP/secondary-02.test.local@TEST.LOCAL -mapuser secondary2-user@TEST.LOCAL -crypto AES256-SHA1 -ptype KRB5_NT_PRINCIPAL -pass * -in C:\keytabs\filename2.keytab -out C:\keytabs\filename3.keytab This will result in the creation of a file named filename3.keytab containing all three added SPNs.

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