143.204.73.10
server-143-204-73-10.nrt12.r.cloudfront.net
143.204.73.31
server-143-204-73-31.nrt12.r.cloudfront.net
143.204.73.37
server-143-204-73-37.nrt12.r.cloudfront.net
143.204.73.98
server-143-204-73-98.nrt12.r.cloudfront.net

2600:9000:21e1:1e00:d:393d:e9c0:93a1
2600:9000:21e1:2200:d:393d:e9c0:93a1
2600:9000:21e1:6e00:d:393d:e9c0:93a1
2600:9000:21e1:8400:d:393d:e9c0:93a1
2600:9000:21e1:a00:d:393d:e9c0:93a1
2600:9000:21e1:b000:d:393d:e9c0:93a1
2600:9000:21e1:b600:d:393d:e9c0:93a1
2600:9000:21e1:f200:d:393d:e9c0:93a1

in1-smtp.messagingengine.com.
in2-smtp.messagingengine.com.