Hello, You should look at saslauthd. I have used it in the past to do precisely this; Authenticate "virtual" users for access to sendmail and cyrus-imapd. Regards, Dan ________________________________ From: centos-bounces at centos.org [mailto:centos-bounces at centos.org] On Behalf Of sync Sent: Wednesday, 21 April 2010 9:40 PM To: CentOS mailing list Subject: [CentOS] Sendmail using LDAP authentication problem Hi , all ; My openldap is running fine . Sendmail configuration is done. I want to use LDAP authentication only. User of my mailserver should not have a Linux users . I am running CentOS 5.3 i386 . Openldap-2.3.43-3.el5 , sendmail-8.13.8-2.el5 All the software is already installed and running . LDAP has the following tree: uid=xxx, ou=People, dc=test, dc=com I want to know what I've to change which configuration file and any pointer to the doc with clearly says the configuration . Any help will be appreciated. Please I am kind of stuck and waiting for anyone who can clear this cloud. Thank you in advance ~