Re: [Exim] Concept of LDAP usage

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Auteur: Torsten Schlabach
Date:  
À: exim-users
Sujet: Re: [Exim] Concept of LDAP usage
Jan-Piet,

thank you for the fast answer. As I was already guessing when choosing the
subject for my email, I got the concept of ldapauth wrong. I was thinking
along the llines of logging into the LDAP server with some kind of superuser
and
then doing a lookup of the credentials and comparing the password. I was not
really aware that the LDAP server offers authentication as a service. I also
had to set some permissions in my LDAP server to make this work.

Do you know what kind of LDAP objects this works for? What attributes does
the LDAP server use to decide if it authorizes someone or not? (The question
might be off-topic but I think it matters to a lot of people who are setting
up Exim for LDAP auth.)

Also the "inner lookup" solved a problem that I found I had just when I got
around the other one. I have instances of inetOrgPerson in my LDAP server.
Their DN is not the username. But I understand I will be able to cope with
that
using the inner lookup in our example to search for the username and find
the DN.

Great help! Thank you!

Take care!

Torsten

> The example you quote builds a distinguished name and tries to bind as
> with the credentials given during the authentication, which is the only
> way
> possible if your LDAP server doesn't hold passwords in clear text.
>
> This works fine for me; it takes the userid and the password given during
> the authentication phase, looks up the DN of the LDAP user (the inner
> lookup
> ldapdn) because I cannot construct the DN, and then tries to bind as that
> user to the directory, if that user has a mail account. The BASEDN
> variable points to the top of my directory tree as in `BASEDN =
> dc=company,dc=com'
>
> ldap_login:
>    driver = plaintext
>    public_name = LOGIN
>    server_prompts = "Username:: : Password::"
>    server_condition = ${\
>        lookup ldap { \
>        user="${lookup ldapdn
> {ldap:///BASEDN?dn?sub?(&(uid=${quote_ldap:$1})(mail=*))}}" \
>        pass="$2" \
>        ldap:///BASEDN?uid?sub?(&(uid=${quote_ldap:$1})(mail=*)) \
>        }{yes}fail \
>    }
>    server_set_id = $1

>
> All this was built from scraps found on the net.
>
> Regards,
>     -JP

>
>
> On Tue, 24 Feb 2004, Torsten Schlabach wrote:
>
> > I am trying to set up SMTP auth with LDAP; especially to support the
> LOGIN
> > mechanism. (Guess for what MTA ...?)
> >
> > What confuses me in the first place is that some example (in the Exim
> spec,
> > which is the only documentation that I stick to as a lot of the stuff
> out
> > there on the net is still 3.x and therefore outdated) use the lookup
> ldap way
> > while the specific example for the LOGIN authenticator
> >
> > (from Section 34.3)
> >
> > login:
> >     driver = plaintext
> >     public_name = LOGIN
> >     server_prompts = Username:: : Password::
> >     server_condition = ${if ldapauth \
> >       {user="cn=${quote_ldap_dn:$1},ou=people,o=example.org" \
> >       pass=${quote:$2} \
> >       ldap://ldap.example.org/}{yes}{no}}
> >     server_set_id = uid=$1,ou=people,o=example.org

> >
> > is using ldapauth.
> >
> > So what's happening to my understanding is that it is not trying to look
> up
> > the user credentials on the LDAP server but it is trying to log in to
> LDAP
> > using the credentials of the person who is trying to send mail with that
> MTA.
>
>
> --
>
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