Need help to "virtual host" one of my domains

Discussion in 'Server Operation' started by wpwood3, Jul 22, 2008.

  1. wpwood3

    wpwood3 New Member

    I have a Windows web server (Server-B) that currently has DNS and mail handled by someone else. Let's say the domain is

    I also have a linux server (Server-A) running ISPConfig, CentOS, Postfix and Dovecot (Perfect Server) that handles my other domains. Let's say the domain here is

    What I want to do is change the nameservers at my domain registrar to point to Server-A's name servers and set up mail on Server-A for users to use. Basically, I want to dump the virtual hosting I am using for Server-B and do it all on Server-A. I can't eliminate Server-B because the web apps I run there are only Windows based.

    I know how to handle changing the nameservers. What I am unsure of is getting the email configured so users can send and receive email since the web server is not located on Server-A and the users don't have accounts on Server-A.

    Hopefully, all of this makes sense...
    Can someone sketch out what I need to do?
  2. wpwood3

    wpwood3 New Member


    After reading and re-reading several of the email related How-to's here it seems like I can take one of these three paths:

    1) Use Eliufoo Mahinda's How To Configure ISP Mail Server With Virtual Users/Domains On Centos 5.0 Using Postfix, Dovecot, MySQL, phpMyAdmin, TLS/SSL

    2) Use Falco's Virtual Users And Domains With Postfix, Courier And MySQL (CentOS 5.1)

    3) Or Joe Topjian's Virtual Hosting with Postfix

    I'm not sure which is the better path. Unfortunately, Falco's How-to uses Courier and I have Dovecot.

    Why isn't there a How-to for those of us that have the "Perfect Server" configuration? I don't want to risk breaking my ISPConfig 2 setup while I'm trying to add a feature that will be included in ISPConfig 3. This is frustrating. :(
    Last edited: Jul 22, 2008
  3. wpwood3

    wpwood3 New Member

    Another thought

    Maybe I'm making this too complex by going the virtual user route.
    I only have a handful of users to worry about. The easier way may be to just add real users to Server-A and set up email accounts there for them.
    dns on Server-A would look like this: and would have A-records that point to the IP for Server-B would be added as an A-record and MX record on Server-A for mail

    If I do that I would still have the full functionality of ISPConfig.
    I don't know how this setup would handle users that need to send and receive emails on both domains. ie- [email protected] and [email protected]

    I like the potential simplicity but, I'm still not sure how to do all of this properly.

  4. falko

    falko Super Moderator ISPConfig Developer

    You cannot use virtual users together with ISPConfig!

    I'd simply create a web site for in ISPConfig and create your email users with ISPConfig. You don't need to use the web site on server A (the DNS records are pointing to server B).
  5. wpwood3

    wpwood3 New Member

    Thanks Falko.

    Could I create a co-domain instead? (and point the A-record to server B)
    That way each current user on would also receive email sent to
    So email sent to [email protected] would come to [email protected]. Correct? Otherwise, I can't have 2 users on Server-A with the username of "joe".

    Also, how do I setup Postfix on Server-A so applications on Server-B can send mail? Can I simply add the IP of Server-B to the mynetworks variable in or is there more involved?
    Last edited: Jul 23, 2008
  6. falko

    falko Super Moderator ISPConfig Developer

    Yes, you can do that.
    Usually you create the email addresses as aliases, for example [email protected] would go to web1_joe, and [email protected] would go to web2_joe...

    Take a look here:
  7. wpwood3

    wpwood3 New Member

    I think you misunderstood what I want to do with the email...

    Server-A has Postfix on it
    Server-B has applications on it that need to be able to send mail but there is no mailserver on Server-B.

    I want Server-B to be able to use my mail server on Server-A.

    How do I configure Postfix on Server-A to accept and send email that comes from applications on Server-B?

    I know I can simply create a valid mail account on Server-A and use smtp to send mail from Server-B to A. Is that the best way?
    Last edited: Jul 23, 2008
  8. falko

    falko Super Moderator ISPConfig Developer

    You must either program your apps to use SMTP-AUTH (i.e., you create a user account with a password for them on server A), or you add server B's IP address to mynetworks on server A.

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