Setup guide (Kerberos)

Our add-ons for Jira, Confluence, Bitbucket, Crucible, and Bamboo follow an almost identical pattern. If you have one of those products, this guide is for you.

Introduction

This guide will establish password-less Integrated Windows Authentication single sign-on for a JIRA instance available at https://issues.example.com. The Windows uses are logged into their computers using the Active Directory domain EXAMPLE.LOCAL

In this example, we assume a Microsoft Active Directory/LDAP User Directory has already been set up for the same domain.

We also assume that you have Domain Admin rights such that you can create and configure user accounts in AD. If you don't have these permissions yourself, you might have to ask a colleague for help.

We recommend setting up a test environment before you go to production.

This youtube video shows the necessary steps to set up Kerberos login and how the login experience will be when it is configured.

Setup wizard

In our add-on configuration page, click Run Kerberos Setup Wizard. 

This wizard helps you in the following ways:

  • It helps you collect some essential information about your environment.

  • It shows you how to create and/or configure an Active Directory account. 

  • It shows you the ktpass command you will use to create a Kerberos keytab file, which our plugin needs to authenticate users. 

Start page

In many cases, the wizard can suggest appropriate configuration values for you automatically.

If this is the case, you will be notified. You might want to jump straight to the task summary using the suggested values instead of going through each step.

For this guide, though, we will run through each step of the wizard.

Active Directory Connection

Connecting to your Active Directory lets the wizard inspect your AD, suggest values, and validate that your configuration is valid. 

You can choose a pre-configured User Directory, or connect to an Active Directory server of your choice:

Canonical hostname

If issues.example.local is a DNS CNAME record, say for server123.example.local, then the canonical name is server123.example.local

Otherwise, if it's a DNS A record, then the canonical name is issues.example.com.

Usually, the wizard can determine this for you by looking it up in DNS on the server.

Note that even if you access JIRA using the short name http://issues, the canonical name is always in the FQDN form. (It is never just issues, but issues.example.com)

Kerberos Realm name

The Kerberos Realm name looks something like EXAMPLE.LOCAL or ACCOUNTING.COMPANY.COM

It is your Active Directory Domain name in upper case, dot-separated format.

If the wizard can't look this up in AD, it will instruct you on how to determine this on your client.

Active Directory account

Kerberos services need to be mapped to an Active Directory account. We recommend you use a separate AD account to map each Kerberos service.

Unless your instance is already mapped, the wizard will suggest an account name such as svc-jirasso-issues.

Encryption types

The wizard will suggest the strongest encryption type supported by your environment.

Some factors which may limit your choice of encryption strength:

  • If your Domain Functional Level is Window 2003, then only RC-4 is supported.

  • AES-256 is only supported if the Java used for running your Atlassian product has the Unlimited Strength Policy Files installed


Enabling AES 256 support in Java

If your service is already mapped to an account, then the strongest configured encryption type for that account is recommended. 

In this case, the wizard has recommended AES-256:

Task summary 

The final page of the wizard starts by displaying the configuration determined in the previous steps:

 

Step 1 of the task list describes how to create and/or configure the service account.

Depending on your AD permissions, you might need to hand this task over to your AD team.

The account svc-jirasso-issues needs to be created with "password never expires."

Please note you will need to dedicate account svc-jirasso-issues to only keytab export since running the ktpass command will invalidate the user password. So always set up using another account for user directory synchronization.

And also, never reuse the same user account in AD for more domains or environments. Always create a new user account every time you need to run ktpass when setting up against a new domain.

 

Then, in the account options, we need to enable "This account supports Kerberos AES 256 bit encryption":

 

Step 2:

Shows you how to create a keytab file using ktpass. Again, this is a task you might have to delegate to your AD team.

Step 3:

Finally, you may upload the keytab file created. After the upload has finished, a login test will be performed. 

Note that if you have multiple domains, then you are offered to add keys to the existing keytab file.


A quick review of the syntax:

Command / parameter

Description

Command / parameter

Description

1 ktpass

ktpass is pre-installed in Windows 2008 onward. Located in c:\Windows\System32

1 /princ HTTP/issues.example.com@EXAMPLE.LOCAL

HTTP is always used for web servers, also when using https.

issues.example.com is the canonical DNS name of JIRA

EXAMPLE.LOCAL is the Kerberos realm name of the Active Directory Domain

1 /mapuser svc-jirasso-issues@EXAMPLE.LOCAL

Maps the /princ name above to the account svc-jirasso-issues.

ktpass will add this attribute on the account:

1 servicePrincipalName: HTTP/issues.example.com
1 /crypto AES2568-SHA1

Specifies the encryption type used when generating keys in the keytab. Must match the account supported encryption type.

1 /ptype KRB5_NT_PRINCIPAL

The general ptype, recommended by Microsoft.

1 /out c:\issues.example.com

Output location of the generated keytab file



Running the ktpass command will output a keytab file and register issues.examples.com as an HTTP Kerberos service.

Specifically, ktpass will: 

  • Add a servicePrincipalName attribute on the account with the value HTTP/issues.example.com.

  • Set the userPrincipalName attribute to  HTTP/issues.example.com.

  • Ask the admin to provide a password and confirm it.

  • Set that password on the account.

  • Generate a keytab file with an AES-256 key for the principal  HTTP/issues.example.com@EXAMPLE.LOCAL.

Note that ktpass must be running in a "run as administrator" cmd window by a user with Domain Admin permissions.

Browser configuration

After uploading the keytab file, you will be redirected to the Kerberos Authentication Test page.

If you're lucky, this test will succeed on your first try:

Internet Explorer

In our case, we got a failing test. Internet Explorer has not been configured to send Kerberos tickets to issues.example.com. It falls back to sending NTLM tickets instead (which is seen as a username and password popup)

We need to make sure issues.example.com is placed in the Local Intranet Security Zone since that is a requirement for Internet Explorer to send Kerberos tickets.

 

The zone settings are usually set enterprise-wide using Group Policies. Here's the GPO we used to place *.example.com and issues.example.com in the Local Intranet Zone (Zone 1):

Other browsers

For more details on configuring Zone settings, and configuring Chrome and Firefox on Windows, Mac, and Linux, see our Browser Configuration Guide.