In this guide:

• Supported LDAP services
• Username considerations with LDAP
• Two-factor authentication
• Configuring LDAP with your GitHub Enterprise instance
• LDAP attributes
• Viewing and creating LDAP users
• Updating LDAP accounts
• Revoking access to your GitHub Enterprise instance

Supported LDAP services

GitHub Enterprise integrates with these LDAP services:

• Active Directory
• FreeIPA
• Oracle Directory Server Enterprise Edition
• OpenLDAP
• Open Directory
• 389-ds

Username considerations with LDAP

GitHub Enterprise usernames can only contain alphanumeric characters and dashes (-). GitHub Enterprise will normalize any non-alphanumeric character in your account's username into a dash. For example, a username of gregory.st.john will be normalized to gregory-st-john. Note that normalized usernames also can't start or end with a dash. They also can't contain two consecutive dashes.

Usernames created from email addresses are created from the normalized characters that precede the @ character.

If multiple accounts are normalized into the same GitHub Enterprise username, only the first user account is created. Subsequent users with the same username won't be able to sign in.

This table gives examples of how usernames are normalized in GitHub Enterprise:

Username	Normalized username	Result
Ms.Bubbles	ms-bubbles	This username is created successfully.
!Ms.Bubbles	-ms-bubbles	This username is not created, because it starts with a dash.
Ms.Bubbles!	ms-bubbles-	This username is not created, because it ends with a dash.
Ms!!Bubbles	ms--bubbles	This username is not created, because it contains two consecutive dashes.
Ms!Bubbles	ms-bubbles	This username is not created. Although the normalized username is valid, it already exists.
Ms.Bubbles@example.com	ms-bubbles	This username is not created. Although the normalized username is valid, it already exists.

Two-factor authentication

When using LDAP or built-in authentication, two-factor authentication is supported. Organization administrators can require members to have two-factor authentication enabled.

Configuring LDAP with your GitHub Enterprise instance

After you configure LDAP, users will be able to sign into your instance with their LDAP credentials. When users sign in for the first time, their profile names, email addresses, and SSH keys will be set with the LDAP attributes from your directory.

When you configure LDAP access for users via the Management Console, your license seats aren't used until the first time a user signs in to your instance. However, if you create an account manually using site admin settings, the license seat is immediately accounted for.

1. In the upper-right corner of any page, click .

2. In the left sidebar, click Management Console.

3. In the left sidebar, click Authentication.

4. Under "Authentication", select LDAP.

5. Add your configuration settings.

LDAP attributes

Use these attributes to finish configuring LDAP for your GitHub Enterprise instance.

Attribute name	Type	Description
Host	Required	The LDAP host, e.g. ldap.example.com or 10.0.0.30. If the hostname is only available from your internal network, you may need to configure your GitHub Enterprise instance's DNS first so it can resolve the hostname using your internal nameservers.
Port	Required	The port the host's LDAP services are listening on. Examples include: 389 and 636 (for LDAPS).
Encryption	Required	The encryption method used to secure communications to the LDAP server. Examples include plain (no encryption), SSL/LDAPS (encrypted from the start), and StartTLS (upgrade to encrypted communication once connected).
Domain search user	Optional	The LDAP user that performs user lookups to authenticate other users when they sign in. This is typically a service account created specifically for third-party integrations. Use a fully qualified name, such as cn=Administrator,cn=Users,dc=Example,dc=com. With Active Directory, you can also use the [DOMAIN]\[USERNAME] syntax (e.g. WINDOWS\Administrator) for the domain search user with Active Directory.
Domain search password	Optional	The password for the domain search user.
Administrators group	Optional	Users in this group are promoted to site administrators when signing into your appliance. If you don't configure an LDAP Administrators group, the first LDAP user account that signs into your appliance will be automatically promoted to a site administrator.
Domain base	Required	The fully qualified Distinguished Name (DN) of an LDAP subtree you want to search for users and groups. You can add as many as you like; however, each group must be defined in the same domain base as the users that belong to it. If you specify restricted user groups, only users that belong to those groups will be in scope. We recommend that you specify the top level of your LDAP directory tree as your domain base and use restricted user groups to control access.
Restricted user groups	Optional	If specified, only users in these groups will be allowed to log in. You only need to specify the common names (CNs) of the groups, and you can add as many groups as you like. If no groups are specified, all users within the scope of the specified domain base will be able to sign in to your GitHub Enterprise instance.
User ID	Required	The LDAP attribute that identifies the LDAP user who attempts authentication. Once a mapping is established, users may change their GitHub Enterprise usernames. This field should be sAMAccountName for most Active Directory installations, but it may be uid for other LDAP solutions, such as OpenLDAP. The default value is uid.
Profile name	Optional	The name that will appear on the user's GitHub Enterprise profile page. Unless LDAP Sync is enabled, users may change their profile names.
Emails	Optional	The email addresses for a user's GitHub Enterprise account.
SSH keys	Optional	The public SSH keys attached to a user's GitHub Enterprise account. The keys must be in OpenSSH format.
GPG keys	Optional	The GPG keys attached to a user's GitHub Enterprise account.
Disable LDAP authentication for Git operations	Optional	If selected, turns off users' ability to use LDAP passwords to authenticate Git operations.
Enable LDAP certificate verification	Optional	If selected, turns on LDAP certificate verification.
Synchronization	Optional	If selected, turns on LDAP Sync.

Disabling password authentication for Git operations

Select Disable LDAP authentication for Git operations in your LDAP settings to enforce use of personal access tokens or SSH keys for Git access, which can help prevent your server from being overloaded by LDAP authentication requests. We recommend this setting because a slow-responding LDAP server, especially combined with a large number of requests due to polling, is a frequent source of performance issues and outages.

When this option is selected, if a user tries to use a password for Git operations via the command line, they will receive an error message that says, Password authentication is not allowed for Git operations. You must use a personal access token.

Enabling LDAP certificate verification

Select Enable LDAP certificate verification in your LDAP settings to validate the LDAP server certificate you use with TLS.

When this option is selected, the certificate is validated to make sure:

• The certificate Common Name (CN) matches the LDAP hostname
• The certificate is not expired
• The certificate is signed by a trusted certificate authority (CA)

Enabling LDAP Sync

Select Synchronization in your LDAP settings to enable LDAP Sync.

LDAP Sync lets you synchronize GitHub Enterprise team members and team roles against your established LDAP groups. This lets you establish role-based access control for users from your LDAP server instead of manually within GitHub Enterprise.

As part of its optimization configuration, LDAP Sync will not transfer your nested team structure. To create child and parent team relationships, you must manually recreate the nested team structure and sync it with the corresponding LDAP group. For more information, see "Creating teams"

Supported LDAP group object classes

GitHub Enterprise supports these LDAP group object classes. Groups can be nested.

• group
• groupOfNames
• groupOfUniqueNames
• posixGroup

Viewing and creating LDAP users

You can view the full list of LDAP users who have access to your instance and provision new users.

1. Sign in to your GitHub Enterprise instance at http(s)://HOSTNAME/login.

2. In the upper-right corner of any page, click .

3. In the left sidebar, click LDAP users.

4. To search for a user, type a full or partial username and click Search. Existing users will be displayed in search results. If a user doesn’t exist, click Create to provision the new user account.

Updating LDAP accounts

Unless LDAP Sync is enabled, changes to LDAP accounts are not automatically synchronized with GitHub Enterprise.

• To use a new LDAP admin group, users must be manually promoted and demoted on GitHub Enterprise to reflect changes in LDAP.
• To add or remove LDAP accounts in LDAP admin groups, promote or demote the accounts on GitHub Enterprise.
• To remove LDAP accounts, suspend the GitHub Enterprise accounts.

Manually syncing LDAP accounts

1. Sign in to your GitHub Enterprise instance at http(s)://HOSTNAME/login.

2. In the upper-right corner of any page, click .

3. In the search field, type the name of the user and click Search.

4. In the search results, click the name of the user.

5. In the upper-right corner of the page, click Admin.

6. In the left sidebar, click Admin.

7. Under "LDAP," click Sync now to manually update the account with data from your LDAP server.

You can also use the API to trigger a manual sync.

Revoking access to your GitHub Enterprise instance

If LDAP Sync is enabled, removing a user's LDAP credentials will suspend their account after the next synchronization run.

If LDAP Sync is not enabled, you must manually suspend the GitHub Enterprise account after you remove the LDAP credentials. For more information, see "Suspending and unsuspending users".