23.22.167.37
ec2-23-22-167-37.compute-1.amazonaws.com
3.214.66.53
ec2-3-214-66-53.compute-1.amazonaws.com
34.197.13.100
ec2-34-197-13-100.compute-1.amazonaws.com

us-smtp-inbound-1.mimecast.com.
us-smtp-inbound-2.mimecast.com.