The mod_auth_ntlm_winbind module provides authentication and authorisation over the web against a microsoft windows nt/2000/xp/etc or samba domain controller using samba's winbind daemon running on the same machine apache is running on.

if you're considering using this module, you should be aware that ntlm isn't regarded as very secure by modern standards - even microsoft no longer recommends its use - and where possible, you probably want to use kerberos with negotiate auth over https instead (see debian package libapache2-mod-auth-kerb).