Running Postfix and Dovecot on separate IPs

Hi all,

I’m a relatively new Virtualmin user and so far am really liking the control panel and its interface and features.

I do have one question, though.

I have a couple IP addresses assigned to my server and I want to split services up among them, so to speak. For example, I want HTTPD to be bound to one IP, while Dovecot and Postfix are bound to another IP, that way I can set up reverse DNS correctly.

Let’s say for the sake of security that I have these two IPs on my server (I actualy have 4 total):

  • 1.2.3.4
  • 5.6.7.8

I want to bind HTTPD to 1.2.3.4 (the default IP configured in Virtualmin), and have all domain DNS records except for mail.domain.tld point to that address.

Then, I want to have 5.6.7.8 used only for Dovecot and Postfix, e.g. those are the only two services that would be bound to that address. Then, I could set up a reverse DNS record, say, rs1.mx.mail.airshock.net, to point to that address and have the hostname of Postfix point there as well (so outgoing mails would appear to originate from that address).

Not only that, but I want mail.domain.tld to automatically point to 5.6.7.8 rather than 1.2.3.4, even when a new virtual server is created.

Is this possible, and if so, how would I go about setting this up? Currently e-mails from my server are getting blocked by other networks because I don’t have reverse DNS configured properly (or something), but I can’t configure that until I can get Dovecot and Posfix bound to this other address.

Note: In theory I would only need to bind Postfix to another address, but if I can do the same for Dovecot that’d be awesome too.

Thanks in advance for any assistance provided. Hopefully I can get this set up as soon as possible because many of the clients I host sites for are reporting, as mentioned above, that networks are blocking e-mails sent from my server.

Thanks!
-Logan

Hello Logan,

Are you behind a router in this setup? If so, you could just point your port forwards for 25 (SMTP), 465 (SMTPS), 587 (Alternate SMTP), 143 (IMAP), 993 (IMAPS), 110 (POP3), etc. to your 5.6.7.8 address and then port 80 (HTTP) and 443 (HTTPS) to your 1.2.3.4 address.

As far as configuring virtualmin to point all postfix, dovecot, spamassassin, etc. protocols and functions to 5.6.7.8, I’m not sure how to do that.


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