18.245.124.107
server-18-245-124-107.dfw57.r.cloudfront.net
18.245.124.18
server-18-245-124-18.dfw57.r.cloudfront.net
18.245.124.48
server-18-245-124-48.dfw57.r.cloudfront.net
18.245.124.80
server-18-245-124-80.dfw57.r.cloudfront.net

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