Mail Server with Public IP question.

Discussion in 'Server Operation' started by thavaht, Oct 10, 2008.

  1. thavaht

    thavaht New Member

    Hi all,

    I’m looking for help on the following question:
    I’m running a web server and mail server on different machines on my LAN and I’ve configured Bind to resolve internally for the clients in the LAN. That time I had only one public IP address.

    Now a have a second public IP and want the mail server to use its own public IP but having the mail server still accessible internally.
    Is that possible to have the mail server directly connected to the WAN and to the LAN at the same time? Can I use two network cards?

    Another question is what are the concerns if putting the public IP on the server? TIA.
  2. marpada

    marpada New Member

    You can configure your firewall/router to port-forward port 25 of your public IP address to the port 25 of the mail server in your LAN, and the same to port 80 for web server and port 53 for DNS (so you can have two servers or more using the same public IP).
    For DNS configure two views, one for your internal network to resolve to internal IPs and one for queries from internet to resolve to public IP.
    Last edited: May 13, 2011
  3. thavaht

    thavaht New Member

    Thanks for replying.
    Your suggestion matches what I’m actually doing now:
    I’m port-forwarding my public IP to the servers in the LAN.

    I had problems with my provider complaining that some computer in my LAN was spreading virus and my connection being suspended. This is one of the reasons why I want the mail server to have its own public address, but I want it also accessible in the LAN.
  4. falko

    falko Super Moderator ISPConfig Developer

    Does your router support multiple public IP addresses?
  5. thavaht

    thavaht New Member

    I have a Linksys WRT54G router connected to a cable modem. My router supports only one public IP address.
    I thought I could put a switch after the modem and have the router and the mail server connected to that switch, each with its public IP.


  6. marpada

    marpada New Member

    Last edited: May 13, 2011

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