[Techtalk] Stupid DNS questions

[Kai MacTane]

At 3/8/04 08:11 AM , Michelle Murrain wrote:

>I hate to show my ignorance, especially given that I've been running DNS 
>servers for a year or so.

"The only stupid question is the one you don't ask."

>I need to create a system where I can easily change DNS info (add 
>subdomains, change IPs) via a web interface (so multiple people can have 
>access to that - I'm assuming I'll use WebMin). The challenge is, how to 
>make sure all of the DNS info for all three servers is updated properly.

You'll want to make one of those masters be a secondary (slave).

>I'm not exactly certain how slave DNS servers work, which is part of my 
>issue. RIght now, in order to change DNS info on the domains I'm running 
>DNS for, I update the respective db files and named.conf on both servers. 
>I'd like to do it only once.

No kidding. If the two get out of sync, you could have all sorts of 
interesting problems.

>  I could set up the second DNS server on the local network to be a slave 
> to the first, but I was afraid if for some reason the first became 
> unavailable, the second would then not work, which is then besides the 
> point (which also makes me ponder the issue of the remote slave).

Assuming you configure things right, the slave should keep right on serving 
out information even if the master goes down. That's exactly what a 
secondary name server is *for*.

>Also, if anyone has any other suggestions for how to do this, I'm happy to 
>take them.

Cookbook style recipe follows.

/etc/named.conf on master:

    options {
       directory "/where/ever";
    };
    [other global options as needed]
    zone "somedomain.tld" in {
       type master;
       file "zones/master/somedomain.tld";
    };
    [repeat zones as needed]

/etc/named.conf on slave:

    options {
       directory "/where/ever";
    };
    [other global options as needed]
    zone "somedomain.tld" in {
       type slave;
       file "zones/slave/somedomain.tld";
       masters { 1.2.3.4; };
    };
    [repeat zones as needed]

The IP address in the "masters" command in the secondary server's 
named.conf should, of course, be that of the primary name server.

And that's about it! Set up your named.conf files, reload the configs, and 
you should be good to go. Unless I forgot something completely boneheaded, 
which is possible.

                                                 --Kai MacTane
----------------------------------------------------------------------
"I am the storm. My voice is the river.
  Take from me, I fade into you..."
                                                 --The Last Dance,
                                                  "Fairytale (the Storm)"