Who is this page for?

This page is intended for everyone who wants to enable his/her ubuntu client to authenticate with an already for authentication configured LDAP server.

Installing and configuring LDAP authentication

1. Install the necessary packages

You will need to install the packages libpam-ldap and libnss-ldap to be able to use LDAP authentication:

$ sudo apt-get install libpam-ldap libnss-ldap

During install you will be asked the following questions:

• The address of the LDAP server used. You can also use a fully qualified domain name here. For example: ldap.example.com

• The distinguished name of the search base. For example dc=example,dc=com

• The LDAP version to use. You usually would choose 3 here.

• If your database requires logging in. You would usually choose no here.

• If you want to make configuration readable/writeable by owner only. A no should be the answer to this.

• A Dialog will follow to explain it cannot manage nsswitch.conf automatically. Just select OK.

• If you want the local root to be the database admin. You would usually choose yes here.

• Again If your database requires logging in. You would usually choose no here.

• Your root login account. For example: cn=manager,dc=example,dc=com

• Your root password.

• After a dialog explaining the different encription methods you will close by selecting OK, you will be asked for the encryption method to use before sending your password. exop is usually a very good choice.

2. Configuring nsswitch.conf

Unfortunately we cannot test if we answered correctly the above questions unless we configure nsswitch.conf first, but this step luckily is pretty easy:

$ sudo vi /etc/nsswitch.conf

and enter the following line, which will replace compat with ldap files:

:%s/compat/ldap files/g

Now you can test if you accomplished the first two steps successfully by using the following line (substitude <someldapuser> with a user known by your LDAP server):

$ getent passwd <someldapuser>

If you get a response, your LDAP nsswitch.conf configuration is correct and all you need to do is to configure PAM.

3. Configuring PAM

The PAM configuration is split in 4 files: common-account, common-auth, common-password and common-session

/etc/pam.d/common-account

$ sudo vi /etc/pam.d/common-account

Change the configuration so that the lines show the following:

account sufficient      pam_ldap.so
account required        pam_unix.so

/etc/pam.d/common-auth

$ sudo vi /etc/pam.d/common-auth

Change the configuration so that the lines show the following:

auth    sufficient      pam_ldap.so nullok_secure
auth    required        pam_unix.so use_first_pass

/etc/pam.d/common-password

$ sudo vi /etc/pam.d/common-password

Change the configuration so that the lines show the following:

password        sufficient      pam_ldap.so
password        required        pam_unix.so nullok obscure min=4 max=8 md5

/etc/pam.d/common-session

$ sudo vi /etc/pam.d/common-session

Change the configuration so that the lines show the following:

session sufficient      pam_ldap.so
session required        pam_unix.so

Notes

Changing the lookup order for ''nsswitch.conf''

While configuring nsswitch.conf you might want to swap around ldap and files to first check your local passwd file before consulting the LDAP server:

passwd: files ldap
group:  files ldap
shadow: files ldap

automatically creating home dir on first logon

You might want to add the following line to your common-session file:

session required        pam_mkhomedir.so

Use ''getent'' to check if your configuration for ''groups'' is correct

You can use the following line to check if your group configuration in PAM and nsswitch.conf is correct (substitude <someldapgroup> with a group known by your LDAP server):

$ getent group <someldapgroup>

Credits

Most of the information used in this document was found on the following page: http://craige.mcwhirter.com.au/blog/archive/2005/01/17/making_a_debian_or_ubuntu_mach

CategoryDocumentation