Documentation: LDAP Update for Active Directory (#13716)

* Adding documentation to 6-LDAP to display how to allow Active Directory logins with or without the user UPN suffix.

* Correcting misspellings and clarifying explanations

* Updating sections to include sample template

* Misc revisions

---------

Co-authored-by: Jeremy Stretch <jstretch@netboxlabs.com>

docs/installation/6-ldap.md

@@ -148,6 +148,126 @@ AUTH_LDAP_CACHE_TIMEOUT = 3600
 !!! warning
     Authentication will fail if the groups (the distinguished names) do not exist in the LDAP directory.
 
+## Authenticating with Active Directory
+
+Integrating Active Directory for authentication can be a bit challenging as it may require handling different login formats. This solution will allow users to log in either using their full User Principal Name (UPN) or their username alone, by filtering the DN according to either the `sAMAccountName` or the `userPrincipalName`. The following configuration options will allow your users to enter their usernames in the format `username` or `username@domain.tld`.
+
+Just as before, the configuration options are defined in the file ldap_config.py. First, modify the `AUTH_LDAP_USER_SEARCH` option to match the following:
+
+```python
+AUTH_LDAP_USER_SEARCH = LDAPSearch(
+    "ou=Users,dc=example,dc=com",
+    ldap.SCOPE_SUBTREE,
+    "(|(userPrincipalName=%(user)s)(sAMAccountName=%(user)s))"
+)
+```
+
+In addition, `AUTH_LDAP_USER_DN_TEMPLATE` should be set to `None` as described in the previous sections. Next, modify `AUTH_LDAP_USER_ATTR_MAP` to match the following:
+
+```python
+AUTH_LDAP_USER_ATTR_MAP = {
+    "username": "sAMAccountName",
+    "email": "mail",
+    "first_name": "givenName",
+    "last_name": "sn",
+}
+```
+
+Finally, we need to add one more configuration option, `AUTH_LDAP_USER_QUERY_FIELD`. The following should be added to your LDAP configuration file:
+
+```python
+AUTH_LDAP_USER_QUERY_FIELD = "username"
+```
+
+With these configuration options, your users will be able to log in either with or without the UPN suffix.
+
+### Example Configuration
+
+!!! info
+    This configuration is intended to serve as a template, but may need to be modified in accordance with your environment.
+
+```python
+import ldap
+from django_auth_ldap.config import LDAPSearch, NestedGroupOfNamesType
+
+# Server URI
+AUTH_LDAP_SERVER_URI = "ldaps://ad.example.com:3269"
+
+# The following may be needed if you are binding to Active Directory.
+AUTH_LDAP_CONNECTION_OPTIONS = {
+    ldap.OPT_REFERRALS: 0
+}
+
+# Set the DN and password for the NetBox service account.
+AUTH_LDAP_BIND_DN = "CN=NETBOXSA,OU=Service Accounts,DC=example,DC=com"
+AUTH_LDAP_BIND_PASSWORD = "demo"
+
+# Include this setting if you want to ignore certificate errors. This might be needed to accept a self-signed cert.
+# Note that this is a NetBox-specific setting which sets:
+#     ldap.set_option(ldap.OPT_X_TLS_REQUIRE_CERT, ldap.OPT_X_TLS_NEVER)
+LDAP_IGNORE_CERT_ERRORS = False
+
+# Include this setting if you want to validate the LDAP server certificates against a CA certificate directory on your server
+# Note that this is a NetBox-specific setting which sets:
+#     ldap.set_option(ldap.OPT_X_TLS_CACERTDIR, LDAP_CA_CERT_DIR)
+LDAP_CA_CERT_DIR = '/etc/ssl/certs'
+
+# Include this setting if you want to validate the LDAP server certificates against your own CA.
+# Note that this is a NetBox-specific setting which sets:
+#     ldap.set_option(ldap.OPT_X_TLS_CACERTFILE, LDAP_CA_CERT_FILE)
+LDAP_CA_CERT_FILE = '/path/to/example-CA.crt'
+
+# This search matches users with the sAMAccountName equal to the provided username. This is required if the user's
+# username is not in their DN (Active Directory).
+AUTH_LDAP_USER_SEARCH = LDAPSearch(
+    "ou=Users,dc=example,dc=com",
+    ldap.SCOPE_SUBTREE,
+    "(|(userPrincipalName=%(user)s)(sAMAccountName=%(user)s))"
+)
+
+# If a user's DN is producible from their username, we don't need to search.
+AUTH_LDAP_USER_DN_TEMPLATE = None
+
+# You can map user attributes to Django attributes as so.
+AUTH_LDAP_USER_ATTR_MAP = {
+    "username": "sAMAccountName",
+    "email": "mail",
+    "first_name": "givenName",
+    "last_name": "sn",
+}
+
+AUTH_LDAP_USER_QUERY_FIELD = "username"
+
+# This search ought to return all groups to which the user belongs. django_auth_ldap uses this to determine group
+# hierarchy.
+AUTH_LDAP_GROUP_SEARCH = LDAPSearch(
+    "dc=example,dc=com",
+    ldap.SCOPE_SUBTREE,
+    "(objectClass=group)"
+)
+AUTH_LDAP_GROUP_TYPE = NestedGroupOfNamesType()
+
+# Define a group required to login.
+AUTH_LDAP_REQUIRE_GROUP = "CN=NETBOX_USERS,DC=example,DC=com"
+
+# Mirror LDAP group assignments.
+AUTH_LDAP_MIRROR_GROUPS = True
+
+# Define special user types using groups. Exercise great caution when assigning superuser status.
+AUTH_LDAP_USER_FLAGS_BY_GROUP = {
+    "is_active": "cn=active,ou=groups,dc=example,dc=com",
+    "is_staff": "cn=staff,ou=groups,dc=example,dc=com",
+    "is_superuser": "cn=superuser,ou=groups,dc=example,dc=com"
+}
+
+# For more granular permissions, we can map LDAP groups to Django groups.
+AUTH_LDAP_FIND_GROUP_PERMS = True
+
+# Cache groups for one hour to reduce LDAP traffic
+AUTH_LDAP_CACHE_TIMEOUT = 3600
+AUTH_LDAP_ALWAYS_UPDATE_USER = True
+```
+
 ## Troubleshooting LDAP
 
 `systemctl restart netbox` restarts the NetBox service, and initiates any changes made to `ldap_config.py`. If there are syntax errors present, the NetBox process will not spawn an instance, and errors should be logged to `/var/log/messages`.