diff --git a/docs/guides/security/authentication/active_directory_authentication.md b/docs/guides/security/authentication/active_directory_authentication.md index 6c1ac9cd62..ed664f99b4 100644 --- a/docs/guides/security/authentication/active_directory_authentication.md +++ b/docs/guides/security/authentication/active_directory_authentication.md @@ -12,34 +12,23 @@ contributors: Steven Spencer, Sambhav Saggi, Antoine Le Morvan, Krista Burdine ## Introduction -Microsoft's Active Directory (AD) is, in most enterprises, the de facto -authentication system for Windows systems and for external, LDAP-connected -services. It allows you to configure users and groups, access control, -permissions, auto-mounting, and more. +In most enterprises, Microsoft's Active Directory (AD) is the default authentication system for Windows systems and for external, LDAP-connected services. It allows you to configure users and groups, access control, permissions, auto-mounting, and more. -Now, while connecting Linux to an AD cluster cannot support _all_ of the -features mentioned, it can handle users, groups, and access control. It is even -possible (through some configuration tweaks on the Linux side and some advanced -options on the AD side) to distribute SSH keys using AD. +Now, while connecting Linux to an AD cluster cannot support _all_ of the features mentioned, it can handle users, groups, and access control. It is possible (through some configuration tweaks on the Linux side and some advanced options on the AD side) to distribute SSH keys using AD. -This guide, however, will just cover configuring authentication against Active -Directory, and will not include any extra configuration on the Windows side. +This guide, however, will just cover configuring authentication against Active Directory, and will not include any extra configuration on the Windows side. ## Discovering and joining AD using SSSD !!! Note - Throughout this guide, the domain name `ad.company.local` will be used to - represent the Active Directory domain. To follow this guide, replace it with - the actual domain name your AD domain uses. + The domain name `ad.company.local` throughout this guide will represent the Active Directory domain. To follow this guide, replace it with your AD domain's actual domain name. -The first step along the way to join a Linux system into AD is to discover your -AD cluster, to ensure that the network configuration is correct on both sides. +The first step along the way to join a Linux system into AD is to discover your AD cluster, to ensure that the network configuration is correct on both sides. ### Preparation -- Ensure the following ports are open to your Linux host on your domain - controller: +- Ensure the following ports are open to your Linux host on your domain controller: | Service | Port(s) | Notes | |----------|-------------------|-------------------------------------------------------------| @@ -48,10 +37,10 @@ AD cluster, to ensure that the network configuration is correct on both sides. | LDAP | 389 (TCP+UDP) | | | LDAP-GC | 3268 (TCP) | LDAP Global Catalog - allows you to source user IDs from AD | -- Ensure you have configured your AD domain controller as a DNS server on your - Rocky Linux host: +- Ensure you have configured your AD domain controller as a DNS server on your Rocky Linux host: **With NetworkManager:** + ```sh # where your primary NetworkManager connection is 'System eth0' and your AD # server is accessible on the IP address 10.0.0.2. @@ -61,6 +50,7 @@ AD cluster, to ensure that the network configuration is correct on both sides. - Ensure that the time on both sides (AD host and Linux system) is synchronized (see chronyd) **To check the time on Rocky Linux:** + ```sh [user@host ~]$ date Wed 22 Sep 17:11:35 BST 2021 @@ -75,8 +65,7 @@ AD cluster, to ensure that the network configuration is correct on both sides. ### Discovery -Now, you should be able to successfully discover your AD server(s) from your -Linux host. +Now, you should be able to successfully discover your AD server(s) from your Linux host. ```sh [user@host ~]$ realm discover ad.company.local @@ -94,15 +83,11 @@ ad.company.local required-package: samba-common ``` -This will be discovered using the relevant SRV records stored in your Active -Directory DNS service. +This will be discovered using the relevant SRV records stored in your Active Directory DNS service. ### Joining -Once you have successfully discovered your Active Directory installation from -the Linux host, you should be able to use `realmd` to join the domain, which -will orchestrate the configuration of `sssd` using `adcli` and some other such -tools. +Once you have successfully discovered your Active Directory installation from the Linux host, you should be able to use `realmd` to join the domain, which will orchestrate the configuration of `sssd` using `adcli` and some other such tools. ```sh [user@host ~]$ sudo realm join ad.company.local @@ -114,8 +99,7 @@ If this process complains about encryption with `KDC has no support for encrypti [user@host ~]$ sudo update-crypto-policies --set DEFAULT:AD-SUPPORT ``` -If this process succeeds, you should now be able to pull `passwd` information -for an Active Directory user. +If this process succeeds, you should now be able to pull `passwd` information for an Active Directory user. ```sh [user@host ~]$ sudo getent passwd administrator@ad.company.local @@ -137,8 +121,7 @@ administrator@ad.company.local:*:1450400500:1450400513:Administrator:/home/admin ### Attempting to Authenticate -Now your users should be able to authenticate to your Linux host against Active -Directory. +Now your users should be able to authenticate to your Linux host against Active Directory. **On Windows 10:** (which provides its own copy of OpenSSH) @@ -152,19 +135,13 @@ Last login: Wed Sep 15 17:37:03 2021 from 10.0.10.241 [john.doe@ad.company.local@host ~]$ ``` -If this succeeds, you have successfully configured Linux to use Active -Directory as an authentication source. +If this succeeds, you have successfully configured Linux to use Active Directory as an authentication source. ### Setting the default domain -In a completely default setup, you will need to log in with your AD account by -specifying the domain in your username (e.g., `john.doe@ad.company.local`). If -this is not the desired behavior, and you instead want to be able to omit the -domain name at authentication time, you can configure SSSD to default to a -specific domain. +In a completely default setup, you will need to log in with your AD account by specifying the domain in your username (e.g., `john.doe@ad.company.local`). If this is not the desired behavior, and you instead want to be able to omit the domain name at authentication time, you can configure SSSD to default to a specific domain. -This is actually a relatively simple process, and just requires a configuration -tweak in your SSSD configuration file. +This is actually a relatively simple process, and just requires a configuration tweak in your SSSD configuration file. ```sh [user@host ~]$ sudo vi /etc/sssd/sssd.conf @@ -173,20 +150,15 @@ tweak in your SSSD configuration file. default_domain_suffix = ad.company.local ``` -By adding the `default_domain_suffix`, you are instructing SSSD to (if no -other domain is specified) infer that the user is trying to authenticate as a -user from the `ad.company.local` domain. This allows you to authenticate as -something like `john.doe` instead of `john.doe@ad.company.local`. +By adding the `default_domain_suffix`, you are instructing SSSD to (if no other domain is specified) infer that the user is trying to authenticate as a user from the `ad.company.local` domain. This allows you to authenticate as something like `john.doe` instead of `john.doe@ad.company.local`. -To make this configuration change take effect, you must restart the -`sssd.service` unit with `systemctl`. +To make this configuration change take effect, you must restart the `sssd.service` unit with `systemctl`. ```sh [user@host ~]$ sudo systemctl restart sssd ``` -In the same way, if you don't want your home directories to be suffixed by the domain name, -you can add those options into your configuration file `/etc/sssd/sssd.conf`: +In the same way, if you don't want your home directories to be suffixed by the domain name, you can add those options into your configuration file `/etc/sssd/sssd.conf`: ``` [domain/ad.company.local] @@ -198,8 +170,7 @@ Don't forget to restart the `sssd` service. ### Restrict to certain users -There are various methods to restrict access to the server to a limited list of users, - but this, as the name suggests, is certainly the simplest: +There are various methods to restrict access to the server to a limited list of users, but this, as the name suggests, is certainly the simplest: Add those options into your configuration file `/etc/sssd/sssd.conf` and restart the service: