[NTLUG:Discuss] Dynamic IP and External DNS - is it possible?

[Chris Cox]

Keller Giacomarro wrote:
> This is something of a Linux question, since I'm implementing it in Linux -
> please let me know if this type of query is inappropriate for this list.
> 
> Being the student of networking that I am, I've recently gotten very
> interested in DNS.  To learn more, I'd like to set up an external DNS server
> for my personal domain.  Here's what's setup now:
> 
> kellerg.com points to my RoadRunner cable IP address.  I'm using
> no-ip.comto accomplish this.
> Everytime my IP changes, no-ip updates its DNS A record for kellerg.com with
> my current IP.
> 
> What I want to have happen is DNS requests for my domain should come to my
> bind9 DNS server.  I know that I can just add CNAME and MX records with
> No-IP, but I really just want no-ip to resolve kellerg.com and then pass
> everything else to my nameserver.
> 
> No-IP says this isn't possible without a static IP.  Is that true?

You have to register your nameservers (IPs) as being authoritative for
your domain (zone) so that when people want to query your records, they can.
So... yes... you need a static IP for your nameservers (and you really
should have more than one).

With that said.... friends and family CAN use you as THEIR nameserver.
Thus in the their resolv.conf they would have:

nameserver <your-ip-address>

Of course, you can then be authoritative for ALL domains... AND you'll
need to handle recursive queries (if people find out about your little
nameserver they may ALL try to use it). They could also run their
own DNS servers which are mostly caching and delegate records out to
your nameserver for your domain (zone)... or even forward to it.
But obviously not as ideal as having a TRUE domain nameserver
with a registered static IP(s) associated with your domain (zone).