Multiple Domains Setup for Mail Sending and Receiving

Discussion in 'Installation/Configuration' started by Nyx_, Oct 25, 2022.

  1. Nyx_

    Nyx_ Member HowtoForge Supporter

    Hi Folks, Good day.
    I hope you're doing Ok.

    I'm wondering if this is something possible with ISPConfig...
    I'm looking for a way to have my mail setup to work with multiple domains.

    At the moment, I have a server that hosts several domains and I elected one of this domains to be the mail sending/receiving domain, so the others domains DNS MX records point to this "main" domain.

    Is it possible, via the ISPConfig interface, to have each other hosted domain to behaves as if they have their own Mail Server, including the domains SSL certificates, SMTP banner, etc?

    Thanks in advance.
  2. Taleman

    Taleman Well-Known Member HowtoForge Supporter

    No, unless you set up a separate e-mail server for each domain.
    It is possible to do, but not from ISPConfig panel. But it is considered a bad idea: it leads to complications, restrictions on number of e-mail domains (LE has max 100 domains in one certificate). There are previous discussions about this on this forum, it is a regular occurrence.
    Nyx_ and ahrasis like this.
  3. pyte

    pyte Well-Known Member HowtoForge Supporter

    Can i ask, why you even want this? What is the advantage to just using a single(or multiserver) mailserver for all these domains?
  4. nhybgtvfr

    nhybgtvfr Well-Known Member HowtoForge Supporter

    actually. i think i'd go this route if ispconfig supported postfix SNI.
    yes it's a bit more complicated, but if supported by ispconfig, most, if not all of that SNI setup would be automated, so the only real ongoing complication would be caused by certificates not renewing properly, or not copied over to the mailserver configurations, and it would completely bypass any 100 domains per certificate limit imposed by letsencrypt.

    on the upside, the client side configuration should be much more straightforward and hassle-free, as most mail clients these days start by trying to connect to imap / pop3 / smtp using the same domain as the email address you're configuring, and only then allow a manual setup if that fails, and trying to tell computer illiterate / phobic clients what the mailserver settings are, and where to set them takes up a hell of a lot more of my time than the initial SNI configuration would.

    and if ispconfig supported postfix SNI, it's only a little more work to add support for pure-ftpd SNI, which should be possible now new releases of pure-ftpd-common also include the pure-certd binary. ;)
    Nyx_ likes this.
  5. Nyx_

    Nyx_ Member HowtoForge Supporter

    Thanks for the information @Taleman Very informative. I'll proceed with what's considered the best practice. Thank you.
  6. Nyx_

    Nyx_ Member HowtoForge Supporter

    Hi @nhybgtvfr The main reason is that some client are "picky" about having to inform a different domain name for their clients when configuring the email client. Not a big deal, I was just checking possibilities to deal with these annoyances for now....

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