143.204.55.106
server-143-204-55-106.osl50.r.cloudfront.net
143.204.55.63
server-143-204-55-63.osl50.r.cloudfront.net
143.204.55.78
server-143-204-55-78.osl50.r.cloudfront.net
143.204.55.92
server-143-204-55-92.osl50.r.cloudfront.net

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