Question Mailserver Migration

[P_heck]

Dear all!

Status Quo: Debian 7 Rootserver running Plesk 12.5 serving >10 customer domains including mail services. DNS is externally hosted, no PLESK DNS is used.

I want now to migrate to a new rootserver running latest Debian version and Plesk Onyx. As this is not my first migration, I know how it works with the Migration Manager. But in opposite to the last migration, where I used the customer domain also as the server address for the mailserver in the mail client settings of my customers, I have now switched all customers to use one single domain which I have setup for the mailserver (secured by SSL).

Problem now - if I want to migrate customer by customer over some days, I will face into problems here as the domain used for the mailserver could only be on one server at the same time.

Idea now is to either use a subdomain (where I also have a SSL certificate as I use multi-domain certificates here) of the mailserver domain or to setup a complete new domain for the mailserver usage.

Two questions:

1. Is it possible to setup the mailserver domain on the new server (still DNS pointing on the old one), then creating the subdomain, change DNS to point this subdomain to the new server and configure the migrated customers's mail client to use this one?

2. When using a complete new domain - can I set up the mailserver in Plesk Onyx to use an Let's Encrypt certificate for this domain name for the mailserver?

Any other idea will also be welcome!

Cheers Peter

 

[Bitpalast]

(1.) Yes. However, I suggest to first create the subdomain and then use that subdomain as the second hosts's name.
(2.) Not by default. You'll need to create your SSL cert by an individually installed Let's Encrypt client. The cert cannot be created and maintained by Plesk. When you use a Let's Encrypt cert for you host domain keep in mind that you must renew it periodically, too.

The host does not necessarily need to be named after a 2nd level domain (domain.tld), but can also be a subdomain (chocolate.domain.tld, cream.domain.tld, espresso.domain.tld ...). In our setup here we are using one wildcard certificate, have named all hosts by subdomains to the same 2nd level domain, so that the same certificate can be used on all machines. Wildcard certs are expensive, but the more machines you have, the cheaper it will be per machine. One advantage of the wildcart cert solution is that you are independet from Let's Encrypt validation and renewal procedures.