[Dovecot] Please help: LDAP configuration _almost_ works.

Rob Coward Rob.Coward at game.co.uk
Wed Apr 16 14:17:56 EEST 2008


On Wed, 2008-04-16 at 10:39 +0100, Wojtek Bogusz wrote:
> dear Rob, thank you for support!
> there are small differences in mine and yours config, like:
> 
> - you do not have auth_bind_userdn defined. if i comment my out i cannot 
> authenticate at all - log file:
> auth(default): ldap(wojtek,192.168.0.200): unknown user
> dovecot: auth(default): client out: FAIL^I1^Iuser=wojtek

Our initial connection is made using the "dn" and "dnpass" settings.
This looks up the user's dn based on the "(&(objectClass=user)(mail=%
u))" search criteria.

My understanding of the auth_bind_userdn setting is that it is only
useful if all your users are in a specific tree in the ldap, so that you
can specify (from
http://wiki.dovecot.org/HowTo/DovecotOpenLdap?highlight=%
28auth_bind_userdn%29 ) auth_bind_userdn = uid=%
u,ou=People,dc=_WIZZY_HOSTNAME_,ou=wizzy

This I believe saves the first lookup to find the dn of the user trying
to login. Our users are spread throughout our tree, hence using the
initial lookup as the 'dn'/'dnpass' user to find our user's dn.

If you remove auth_bind_userdn, do you have 'dn' & 'dnpass' setup with a
suitable unprivileged user to allow the initial lookup of the logging-in
user's dn ?

> 
> - you have user_attrs = mail=user, me: user_attrs = 
> homeDirectory=home,uidNumber=uid. but i do not think it make any difference.
> 

Our users login with their email address as the userid - hence
"mail=user" telling dovecot that the userid is stored in the 'mail'
attribute in the ldap results. We dont bother with 'home' or 'uid' as
they are all virtual users, using a fixed uid set by "user_global_uid =
dovecot" and "mail_location: maildir:/data/shared/mailstore/%d/%n"

> - i did not have deref = never. do you know what does it do? i do not 
> understand man ldapsearch explanation :(

something to do with following links to other ldap servers I think. Dont
think its strictly necessary in a single server setup.

> 
> Rob, could you send me your ldap config (/etc/ldap/slapd.conf) please? 
> maybe i am making some simple mistake with my ldap config...

As I said, we use Active Directory (running on Win2k3 servers I
believe), not slapd.

Regards,
Rob


> Rob Coward wrote:
> > I cant help you with what is going wrong for you, but we use dovecot
> > very successfully with ldap lookups against Active Directory, using
> > auth_bind=yes, and it does not require anonymous connections. The
> > initial connection is by an un-privileged user that searches for the
> > user, then a 2nd connection is used, authenticating against AD as the
> > looked up user using the password supplied to dovecot.
> > 
> > Our setup looks like this:
> > 
> > # rpm -q dovecot
> > dovecot-1.0-1.2.0.el5
> > 
> > # dovecot -n
> > # /etc/dovecot.conf
> > protocols: imap pop3
> > login_dir: /var/run/dovecot/login
> > login_executable(default): /usr/libexec/dovecot/imap-login
> > login_executable(imap): /usr/libexec/dovecot/imap-login
> > login_executable(pop3): /usr/libexec/dovecot/pop3-login
> > login_user: dovecotlogin
> > login_process_size: 64
> > login_processes_count: 10
> > login_max_processes_count: 64
> > first_valid_uid: 97
> > default_mail_env: maildir:/data/shared/mailstore/%d/%n
> > mail_location: maildir:/data/shared/mailstore/%d/%n
> > mail_executable(default): /usr/libexec/dovecot/imap
> > mail_executable(imap): /usr/libexec/dovecot/imap
> > mail_executable(pop3): /usr/libexec/dovecot/pop3
> > mail_plugin_dir(default): /usr/lib64/dovecot/imap
> > mail_plugin_dir(imap): /usr/lib64/dovecot/imap
> > mail_plugin_dir(pop3): /usr/lib64/dovecot/pop3
> > auth default:
> >   passdb:
> >     driver: ldap
> >     args: /etc/dovecot-ldap.conf
> >   passdb:
> >     driver: ldap
> >     args: /etc/dovecot-ldap-fr.conf
> >   passdb:
> >     driver: ldap
> >     args: /etc/dovecot-ldap-se.conf
> >   userdb:
> >     driver: ldap
> >     args: /etc/dovecot-ldap.conf
> >   userdb:
> >     driver: ldap
> >     args: /etc/dovecot-ldap-fr.conf
> >   userdb:
> >     driver: ldap
> >     args: /etc/dovecot-ldap-se.conf
> > 
> > # cat /etc/dovecot-ldap.conf
> > hosts = ad.our.net
> > dn=CN=Lookup,CN=Users,DC=our,DC=net
> > dnpass=XXXXXXXX
> > auth_bind = yes
> > ldap_version = 3
> > base = OU=Stores,OU=UK,DC=our,DC=net
> > deref = never
> > scope = subtree
> > user_attrs = mail=user
> > user_filter = (&(objectClass=user)(mail=%u))
> > pass_attrs = mail=user,userPassword=password,mail=userdb_user
> > pass_filter = (&(objectClass=user)(mail=%u))
> > user_global_uid = dovecot
> > user_global_gid = dovecot
> > 
> > We use multiple userdb / passdb definitions and ldap configs in order to
> > limit the searches of our AD schema to specific sub-trees, both for
> > performance and as there are other users elsewhere in our schema that we
> > dont want dovecot to allow to connect.
> > 
> > Hope this helps you.
> > Rob
> > 
> > On Wed, 2008-04-16 at 00:19 +0100, Wojtek Bogusz wrote:
> >>>> /etc/ldap/sldap.conf:
> >>>> access to attr=uid,homeDirectory,uidNumber
> >>>>         by anonymous read
> >>> 	I do not have this in my configuration, and dovecot does indeed use the
> >>> credential I provide to successfully query LDAP for the user based on
> >>> the (mail=%u) criteria.  However, it does not see the reply.
> >>> 	The fact that it does perform the query successfully implies to me that
> >>> it does not use an anonymous connection.  Very puzzling.
> >>
> >> i have no idea what dovecot is doing :-) from the log file it looks like 
> >> there are 2 queries to ldap: 1. to check provided password for provided 
> >> user name, 2. to find a user related information (and from what Steffen 
> >> wrote this one is done with anonymous user - correct?).
> >>
> >> [on the margin: why isn't it done in one query: get me the user related 
> >> information, i am binding with provided user and with provided password. 
> >> this way it would be one query for two things.]
> >>
> >> in my case, i cannot list user related information from ldap in 
> >> anonymous connection even from command line, using: ldapsearch -x -b 
> >> 'ou=Users,dc=frontline' '(&(objectClass=posixAccount)(uid=wojtek))' 
> >> homeDirectory
> >>
> >> so i guess that i have to workout ldap settings for anonymous query. my 
> >> /etc/ldap/slapd.conf related to access permissions is:
> >>
> >> access to dn.children="ou=Users,dc=frontline" 
> >> attrs=uid,homeDirectory,uidNumber
> >>         by anonymous read
> >> access to attrs=userPassword,sambaNTPassword,sambaLMPassword
> >>          by dn="cn=admin,dc=frontline" write
> >>          by anonymous auth
> >>          by self write
> >>          by * none
> >> access to dn.children="ou=Users,dc=frontline"
> >>          by dn="cn=root,ou=Users,dc=frontline" read
> >>          by anonymous auth
> >>          by self write
> >> access to dn.base="" by * read
> >> access to *
> >>          by dn="cn=admin,dc=frontline" write
> >>          by * read
> >>
> >> maybe the problem is here... any hints please?
> >>
> >> regards, Wojtek
> > 


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