52.214.222.255
ec2-52-214-222-255.eu-west-1.compute.amazonaws.com
54.77.4.152
ec2-54-77-4-152.eu-west-1.compute.amazonaws.com

2a05:d018:1c9:4202:433a:d0db:b101:a734
2a05:d018:1c9:4203:c45:e81c:cf62:38fd

mxext1.mailbox.org.
mxext2.mailbox.org.
mxext3.mailbox.org.