DNS with multiple IP addresses

Discussion in 'Installation/Configuration' started by tristanlee85, May 20, 2010.

  1. tristanlee85

    tristanlee85 New Member

    I have created a domain www.cfcoding.com and when creating the site, I selected * for the IP address since I have my server configured for .68 and .69 IPs that I have set from my ISP.

    When creating the DNS record for www.cfcoding.com, it only gave me the option to enter in 1 up (unless I can enter in a list?). The idea is for me is if ns1.tbtech.net seem to be down, I would like it to try and resolve to ns2.tbtech.net which would be my other IP. Is that possible with the way the DNS is setup or am I thinking of a completely different piece of software/hardware to handle this?

    Here is my wizard configuration of my domain:
  2. till

    till Super Moderator Staff Member ISPConfig Developer

    First, DNS Zones normally dont start with www. So make sure that you created a dns zone for cfcoding.com and not for www.cfcoding.com. www.cfcoding.com is a A-Record of the zone cfcoding.com and not a separate zone.

    You can do round robin DNS, this means that you add more then one DNS A-Record for a given domain or subdomain pointing to different IP addresses. But round robin DNS is more a solution for load balancing and not for failover setups, as the client will get a error message if one of the IP addresses dont respond.

    For a failover setup, you use software like this:




    which polls the different servers from time to time to check if they are online.
  3. tristanlee85

    tristanlee85 New Member

    Awesome, thanks. I did catch my error with the zoning and added 2 A-records for domain.com and 2 for www.

    The thing is, I have 2 IPs but they are on the same server so if the server is down it doesn't have a way to failover. I was aiming for the round-robin idea with the IPs since I have 2 separate cable modems and if 1 modem went down, maybe the other one is up (unless my entire cable system goes down).

    Thank you!
  4. tristanlee85

    tristanlee85 New Member

    Also, I realzed that looking at the zones in the image above, the A, MX, and NS records all have a period at the end. Should that be there or does it not matter either way?
  5. till

    till Super Moderator Staff Member ISPConfig Developer

    The period must be there. If you have a fully qualified domain name in dns e.g. www.yourdomain.com, it ahs to end with a dot. Of a record does not end with a dot, then its a relative domain name and the name of the zone gets appended to it.

    So in a zone cfcoding.com, these two A-Records are the same:


    This naming convention is used by all major dns servers incl. BIND and mydns.
  6. tristanlee85

    tristanlee85 New Member

    Cool. Good to know. Thank you!

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