When I do this in SME Server 7 RC2
dig -t MX deps.ufsc.br
; <<>> DiG 9.2.1 <<>> -t MX deps.ufsc.br
;; global options: printcmd
;; connection timed out; no servers could be reached
Then I try in a Server with Gentoo Installed and this work successful,
may be a problem with MX DNS resolution SME Server 7 RC2,
I will see and report to bug tracker
so many thanks