GitLab can be configured to allow your users to sign with their LDAP credentials to integrate with e.g. Active Directory.
The first time a user signs in with LDAP credentials, GitLab will create a new GitLab user associated with the LDAP Distinguished Name (DN) of the LDAP user.
GitLab user attributes such as nickname and email will be copied from the LDAP user entry.
GitLab assumes that LDAP users are not able to change their LDAP 'mail', 'email' or 'userPrincipalName' attribute.
An LDAP user who is allowed to change their email on the LDAP server can [take over any account](#enabling-ldap-sign-in-for-existing-gitlab-users) on your GitLab server.
We recommend against using GitLab LDAP integration if your LDAP users are allowed to change their 'mail', 'email' or 'userPrincipalName' attribute on the LDAP server.
To enable GitLab LDAP integration you need to add your LDAP server settings in `/etc/gitlab/gitlab.rb` or `/home/git/gitlab/config/gitlab.yml`.
In GitLab Enterprise Edition you can have multiple LDAP servers connected to one GitLab server.
Please note that before version 7.4, GitLab used a different syntax for configuring LDAP integration.
The old LDAP integration syntax still works in GitLab 7.4.
If your `gitlab.rb` or `gitlab.yml` file contains LDAP settings in both the old syntax and the new syntax, only the __old__ syntax will be used by GitLab.
# Choose an ID made of a-z and 0-9 . This ID will be stored in the database
# so that GitLab can remember which LDAP server a user belongs to.
# uswest2:
# label:
# host:
# ....
EOS
```
If you are getting 'Connection Refused' errors when trying to connect to the LDAP server please double-check the LDAP `port` and `method` settings used by GitLab.
Common combinations are `method: 'plain'` and `port: 389`, OR `method: 'ssl'` and `port: 636`.
If you are using a GitLab installation from source you can find the LDAP settings in `/home/git/gitlab/config/gitlab.yml`:
```
production:
# snip...
ldap:
enabled: false
servers:
main: # 'main' is the GitLab 'provider ID' of this LDAP server
## label
#
# A human-friendly name for your LDAP server. It is OK to change the label later,
# for instance if you find out it is too large to fit on the web page.
## Enabling LDAP sign-in for existing GitLab users
When a user signs in to GitLab with LDAP for the first time, and their LDAP email address is the primary email address of an existing GitLab user, then the LDAP DN will be associated with the existing user.
If the LDAP email attribute is not found in GitLab's database, a new user is created.
In other words, if an existing GitLab user wants to enable LDAP sign-in for themselves, they should check that their GitLab email address matches their LDAP email address, and then sign into GitLab via their LDAP credentials.
GitLab recognizes the following LDAP attributes as email addresses: `mail`, `email` and `userPrincipalName`.
If multiple LDAP email attributes are present, e.g. `mail: foo@bar.com` and `email: foo@example.com`, then the first attribute found wins -- in this case `foo@bar.com`.