All, For a production environment, I'd like to setup CentOS XEN guests as lightweight as possible. I'd like the XEN guests to be able to send nightly email as all CentOS servers do, but there is no reason to run a mail server as the CentOS Dom0 already has an email server running that can act as an email smart host. The options that seem most appealing to me are either ssmtp or sendmail minimally configured to only run the queuing submission agent. As far as ssmtp, I have not as yet found an CentOS RPM, presumably a Fedora RPM might be suitable. The down side of ssmtp is the lack of queuing should the smart host not be available, not likely but it is possible the email daemon could crash or be down for maintenance or other reason. As far as sendmail, it is simple to switch off the sendmail daemon and only run the queuing submission agent: 1) edit /etc/sysconfig/sendmail and set "DAEMON=no" 2) edit /etc/mail/submit.mc and set FEATURE(`msp', `[IP.of.relayhost]')dnl and of course add an alias for root. Does anyone on this list have experience running a minimal MTA? What other options/software should I be looking at? Any other insights, suggestions or insights? Both the Dom0 and guests are CentOS 5.2. Thanks in advance, Brett