184.73.230.176
ec2-184-73-230-176.compute-1.amazonaws.com
35.171.70.115
ec2-35-171-70-115.compute-1.amazonaws.com
52.55.100.157
ec2-52-55-100-157.compute-1.amazonaws.com

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