MX — receiving servers
PassMX servers are published and their hostnames resolve to IP addresses.
DNS evidence
- 5 gmail-smtp-in.l.google.com (172.253.158.27, 2404:6800:4003:c00::1a)
- 10 alt1.gmail-smtp-in.l.google.com (192.178.230.27, 2404:6800:400b:c01b::1a)
- 20 alt2.gmail-smtp-in.l.google.com (173.194.43.26, 2607:f8b0:400e:c1e::1a)
- 30 alt3.gmail-smtp-in.l.google.com (172.217.78.26, 2607:f8b0:4023:1c05::1a)
- 40 alt4.gmail-smtp-in.l.google.com (142.250.101.26, 2607:f8b0:4023:c06::1b)