Thanks to kind folks on this list, I have managed to get SMTP working and I can receive emails on my box. My domain is ocpdba.net and my hostname is cluster.ocpdba.net I am running my own name servers at ns1.ocpdba.net and can receive emails fine. When I try to send emails this is the error that I get in the returned mail: 554 5.0.0 MX list for cluster.ocpdba.net. points back to cluster.ocpdba.net 554 5.3.5 Local configuration error Here's what my /etc/mail/local-host-names looks like: ---------------------------------------------------- ocpdba.net cluster.ocpdba.net mail.ocpdba.net smtp.ocpdba.net ----------------------------------------------------- Here's what my DNS config looks like: ------------------------------------------------------ ocpdba.net. IN SOA ocpdba.net. ahbaidg.ocpdba.net. ( 0 ; Serial 10800 ; Refresh after 3 hours 3600 ; Retry after 1 hour 604800 ; Expire after 1 week 86400 ) ; Minimum TTL of 1 day ocpdba.net. IN NS ocpdba.net. ocpdba.net. IN A 69.15.57.194 ocpdba.net. IN MX 10 ocpdba.net. ocpdba.net. IN MX 20 ocpdba.net. cluster.ocpdba.net. IN CNAME ocpdba.net. ------------------------------------------------------ Any help is welcome in getting past this issue. Many thanks, Ahbaid