13.211.54.54
ec2-13-211-54-54.ap-southeast-2.compute.amazonaws.com
13.236.51.132
ec2-13-236-51-132.ap-southeast-2.compute.amazonaws.com
3.104.195.245
ec2-3-104-195-245.ap-southeast-2.compute.amazonaws.com

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