Hello, Now the Authentication works with a good BaseDN :-) I need to change it in the LDAP.pm because in my case it must be like 'cn=user,ou=ABC,o=FR' and i don't find where to indicate this syntax in the Config.pm Sure i'm wrong .... Now : If the user already exists, he could log in but if not I have the following message in the log [Error][Kernel::System::User::UserAdd][Line:204]: Need Pw! what's wrong ? I'm using OTRS 1.1.2 thanks I try to use LDAP Auth for agent I check the perl modules : everything seems ok (Net::ldap is ok) in Config.pm I put the 4 lines with parameters $Self->{'SendmailModule'} = 'Kernel::System::Email::SMTP'; $Self->{'SendmailModule::Host'} = '@IPldapserver'; $Self->{'SendmailModule::AuthUser'} = ''; $Self->{'SendmailModule::AuthPassword'} = ''; 1/ I create an agent in the OTRS base. When I try to log through the LDAP auth I 've got this message User: remi.seguy login failed: 'Invalid credentials' (REMOTE_ADDR: mypc). In the ldap properties of my entry in the ldap server, I haven't found any information Pwd (it's an Exchange Server 5.x) and authentification relies on the Windows Dommain Account associated with the email box. Have yo any idea ? Rémi Accédez au courrier électronique de La Poste : www.laposte.net ; 3615 LAPOSTENET (0,34/mn) ; tél : 08 92 68 13 50 (0,34/mn)" Accédez au courrier électronique de La Poste : www.laposte.net ; 3615 LAPOSTENET (0,34/mn) ; tél : 08 92 68 13 50 (0,34/mn)"