We use dovecot in a heterogeneous environment (Windows/Linux desktops and Linux servers). For unified authentication we use a sheaf "Samba/Openldap" (i.e., Samba NT domain with openldap backend and pam/nss_ldap for Linux). Windows users are authenticated well everywhere, but there is one old issue. As "SPA" (NTLM) against NT domain is not supported by dovecot, it is necessary to use default "plain" method. In addition to security problems, it does also a problem of password unification. Each time a user changes the password, he should do it one more time for the mail program.
I know that dovecot supports NTLM, however against local database only (not for NT domain controller). In early versions support of cyrus-sasl (which supports NTLM now) had been incorporated, however it like not work and now is removed. Fortunately, there is a possibility to substitute dovecot-auth executable. Therefore I have tried to make an alternate variant of dovecot-auth, which supports all that we need.
For us, it seems to be more useful to create an auth daemon using cyrus-sasl, rather than to add domain support to existing ntlm code. First of all, it is easier for implementation. Besides it enables use of all mechanisms supported by cyrus-sasl (present and future), including GSSAPI. Anyway, it will be the useful additive to dovecot.
I have made appropriate patches for both dovecot-1.0-stable and dovecot-1.0.alpha1. The idea is to copy "src/auth" to "src/auth-cyrus", strip all unneeded from newly created directory and add cyrus-sasl support. The resulting code probably looks not so elegantly as if it has been written separately, however this way allows to not make a lot of things from the scratch.
The patch against 1.0.alpha1 is here: http://dmitry.butskoy.name/dovecot/dovecot-1.0.alpha1-cyrus.tar.gz . To be more readable, it is not a flat patch (due to a lot of whole files add/remove). It is a tarball with 3 files: a list of files to initial copy from auth/ to auth-cyrus/, a patch for resulting tree, and a script which automates this steps (:-)). (The script should be run in the root of the main source, i.e. a dir with src/ and doc/ subdirs).
I already have successfully tested this patch with PLAIN method. However before testing of other methods, it would be desirable that somebody have looked at it.
Whether someone could check up my patch (just fluently having read), at least for obvious bugs and typos?
Dmitry Butskoy <Dmitry@Butskoy.name>
Saint-Petersburg, Russia
Red Hat Certified Engineer 809003662809495