dynamic ppp hostmasks, additional hosts

[Kevin Darcy]

Craig F. wrote:

> Basically, im after two things, one to know if this is possible, and if so,
> how to go about doing it.
>
> so, i guess its all about IRC, but I have a small NAT network (one IP). I
> have a hostmask like 'ppp-01.isp.com'. What i want is to run a dns on that
> hostmask and resolve requests to 'myhost.ppp-01.isp.com' to the same IP,
> basically for Vhosting on IRC, multiple IRC users on EFNET is a pain in the
> ass with those dumb I:Lines.
> Another problem is that this has to be dynamic, as everytime i connect the
> hostmask changes.
>
> Replys to group obviously.

What a strange term -- "hostmask". In some places, you seem to be using it
synonymously with "address" and in others, synonymously with "domain name".
What I *think* you want is to be able to dynamically update an A record in a
particular zone whenever you connect to the Internet, so that people can find
your server by a fixed, static name. To accomplish this, I don't think you'll
be able to use your ISP's zone, e.g. "isp.com", since they probably would not
want to give your machine update access to it. Rather, you'll probably end up
having to get your own domain, e.g. mydomain.com. Then, you'll have to get
someone to host that domain -- maybe your ISP offers this as a service -- and
give your machine _exclusive_ update access to it, preferably using some sort
of strong authentication, unless you want to trust *everyone* in your ISP's
dialin pool. It doesn't really work for your server to host the domain --
since its address is assigned dynamically, other nameservers will have trouble
finding it to ask it questions.

Now, if you also want to control your address-to-name mapping, this gets a lot
stickier, since the zone which contains these is controlled (presumably) by
your ISP. If this is really a requirement -- and it seems unlikely -- for what
you're trying to do, then you'll have to discuss options with your ISP. It may
be easier and perhaps cheaper in the long run to just arrange for a static
address. Then you could host your own domain, wouldn't need to bother with
dynamic updates, and could just implement the standard "classless delegation"
method (RFC 2317) for the address-to-name mapping.


- Kevin