Question and response
Question
dig cluster1.us.messagelabs.com. MX
Answer
cluster1.us.messagelabs.com. 60 MX 10 mail901.messagelabs.com.
cluster1.us.messagelabs.com. 60 MX 10 mail907.messagelabs.com.
cluster1.us.messagelabs.com. 60 MX 10 mail923.messagelabs.com.
cluster1.us.messagelabs.com. 60 MX 10 mail930.messagelabs.com.
cluster1.us.messagelabs.com. 60 MX 10 mail931.messagelabs.com.
cluster1.us.messagelabs.com. 60 MX 10 mail943.messagelabs.com.
cluster1.us.messagelabs.com. 60 MX 10 mail948.messagelabs.com.
cluster1.us.messagelabs.com. 60 MX 10 mail951.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
mail901.messagelabs.com. 900 A 67.219.246.215
mail907.messagelabs.com. 900 A 67.219.246.208
mail923.messagelabs.com. 900 A 67.219.247.106
mail930.messagelabs.com. 900 A 67.219.247.202
mail931.messagelabs.com. 900 A 67.219.247.204
mail943.messagelabs.com. 900 A 67.219.250.212
mail948.messagelabs.com. 900 A 67.219.250.215
mail951.messagelabs.com. 900 A 67.219.250.218
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0