global.exacttarget.com has no MX records.
Question and response
Question
dig global.exacttarget.com. MX
Answer
The response has no answer records.
Authority
global.exacttarget.com. 300 SOA gtm01.exacttarget.com. hostmaster.exacttarget.com. 2020101447 10800 3600 604800 86400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0