Hi OTRS-users, I´m not sure, that my first message had reached the list, so I send it again: as I told Martin a few weeks ago, we want to use the OTRS via an MS-Exchange-Server (Don´t hit me, it´s an existing and running system) I´m not an experienced LINUX-Admin, so I have a few problems with the mail configuration. First of all, after installing the otrs, I configured the KMail-settings to test whether it is possible to send and receive Emails with the Linux-client via the Exchange-Server. Configuring the outgoing mails as an SMTP with the datas of the Exchange-Server, it works, with sendmail it won´t. Second step was to configure the fetchmail-cron. Trying to send an Email from this account (private) to the office´s account, I saw, that this worked, too. (with a few changes in etc/sysconfig/fetchmail) At last I tried to send replies from otrs to the Test-customer. The only result is an received message, that the used email-address is unknown. Now there could be two problems: Misconfiguration of the Exchange-Server or misconfiguration of sendmail. Question: Must I use sendmail with otrs? If so, must I use a Relay-Server (the Exchange-Server) in the configuration of sendmail? Is there anybody who has experiences with OTRS (or similar) and MS-Exchange? Thanks for your help. Klaus Humme