root@web [/scripts]# exim -bt "cna717@gmail.com"
abc@gmail.com
router = lookuphost, transport = remote_smtp
host gmail-smtp-in.l.google.com [2607:f8b0:400e:c01::1b] MX=5
host gmail-smtp-in.l.google.com [173.194.79.27] MX=5
host alt1.gmail-smtp-in.l.google.com [2a00:1450:4010:c03::1b] MX=10
host alt1.gmail-smtp-in.l.google.com [74.125.142.26] MX=10
host alt2.gmail-smtp-in.l.google.com [2607:f8b0:4002:c01::1b] MX=20
host alt2.gmail-smtp-in.l.google.com [74.125.140.26] MX=20
host alt3.gmail-smtp-in.l.google.com [2607:f8b0:400d:c00::1a] MX=30
host alt3.gmail-smtp-in.l.google.com [173.194.68.26] MX=30
host alt4.gmail-smtp-in.l.google.com [2607:f8b0:400c:c03::1b] MX=40
host alt4.gmail-smtp-in.l.google.com [74.125.131.26] MX=40
root@web [/scripts]# exim -bt "tam.kt@mail.vn"
tam.kt@mail.vn is undeliverable: Unrouteable address
root@web [/scripts]#