Question and response
Question
dig cluster5.us.messagelabs.com. MX
Answer
cluster5.us.messagelabs.com. 60 MX 10 mail910.messagelabs.com.
cluster5.us.messagelabs.com. 60 MX 10 mail911.messagelabs.com.
cluster5.us.messagelabs.com. 60 MX 10 mail922.messagelabs.com.
cluster5.us.messagelabs.com. 60 MX 10 mail927.messagelabs.com.
cluster5.us.messagelabs.com. 60 MX 10 mail947.messagelabs.com.
cluster5.us.messagelabs.com. 60 MX 10 mail950.messagelabs.com.
Authority
messagelabs.com. 180 NS ns-1296.awsdns-34.org.
messagelabs.com. 180 NS ns-1714.awsdns-22.co.uk.
messagelabs.com. 180 NS ns-453.awsdns-56.com.
messagelabs.com. 180 NS ns-520.awsdns-01.net.
Additional
mail910.messagelabs.com. 900 A 67.219.246.211
mail911.messagelabs.com. 900 A 67.219.246.212
mail922.messagelabs.com. 900 A 67.219.247.99
mail927.messagelabs.com. 900 A 67.219.247.195
mail947.messagelabs.com. 900 A 67.219.250.221
mail950.messagelabs.com. 900 A 67.219.250.217
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0