If you need moodle to authenticate users against Microsoft Active Directory there is a nice guide on moodle.org - http://docs.moodle.org/22/en/LDAP_authentication
However I did not succeed after reading it and had to make some additional forum browsing.
I lacked the actual example(s) of working configuration so here I will try to provide one.
This is how my working LDAP Authentication plugin configuration looks like (with SSO enabled):
LDAP server settings
Host URL: 10.1.1.1 (IP of domain controller)
LDAP encoding: utf-8
Hide passwords: yes
Distinguished name: CN=Administrator,OU=Special Accounts,OU=Admin Objects,DC=mydomain,DC=com (account with permission to read users in AD)
User lookup settings
User type: MS ActiveDirectory
Search subcontexts: yes
Deference aliases: no
User attribute: samaccountname (the actual AD attribute to lookup for moodle username)
MS IE fast path?: no
Authentication type: NTLM