65.8.205.31
server-65-8-205-31.gru3.r.cloudfront.net
65.8.205.43
server-65-8-205-43.gru3.r.cloudfront.net
65.8.205.58
server-65-8-205-58.gru3.r.cloudfront.net
65.8.205.73
server-65-8-205-73.gru3.r.cloudfront.net

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