I noticed that some hosting companies providing both DNS and email services irrevocably ties the latter to the former - specifying an external DNS as the authoritative one automatically means not only the suspension of the mail/webmail service, but the deletion of all emails also.
While I understand the practical motivation behind a suspended service, the email deletion clause really surprise me. Moreover, this can be an hassle during a domain and/or email migration.
So:
why so much haste in suspending and deleting the service? There are some imperative technical reasons?
how do you manage such situation (domain and email migration from an hosting provider to another)?
Thanks.
One thing is that IIRC PowerDNS, maybe others used special records in the DNS zone to configure mailboxes and email forwarders. If the zone is no longer present, then also the associated email services will fail.
A more typical logic is that a providers SMTP servers will accept mail for addresses/domains associated with valid user accounts.
Those same SMTP or similarly configured ones are also used as the outgoing mail servers in the users mail clients.
When the domain
example.comchanges their MX records and longer wishes to use the providers mail service and the@example.comaccounts won't get suspended, then mail sent to@example.come-mail addresses by the other customers of that provider will still be accepted for local delivery, rather than routed based on MX records.The remaining customers of that provider, often including the provider themselves, won't be able to send email to the new MX record of
@example.comas longs as there remain any active @example.com accounts on their mailserver(s).Technically it may be possible that separate that logic (i.e. stop accepting incoming email for local delivery but still allow IMAP/POP3/webmail access) but since it is for customers who are leaving anyway, the priority wouldn't be very high...