Searching a simple secure mail realy program

Hi all, I am searching for a secure and simple mail relay program and I was wondering if any of you know of such a tool to be included in the SuSE distro. The intention is simple, i just want to be able to queue outgoing mail or send it directly from the internal network, so nothing fancy, but it must be secure and dependable. Of course alternatives that are not included in the distribution are welcome too. Thanks in advance, Marcel