18.203.167.51
ec2-18-203-167-51.eu-west-1.compute.amazonaws.com
52.214.182.62
ec2-52-214-182-62.eu-west-1.compute.amazonaws.com

eu-smtp-inbound-1.mimecast.com.
eu-smtp-inbound-2.mimecast.com.
service23.mimecast.com.
service24.mimecast.com.