[rbldnsd] rbldnsd, host/zone timing check availability and domain adding

[Michael Tokarev]

Scott, please excuse me for the long delay answering you.
Was quite busy lately...

Scott Haneda wrote:
> Hello, I have deployed rbldnsd on Mac OS X 10.6 Snow Leopard.  I have a few questions as it relates to the project I am trying to make work.
> 
> I will have a need that any additions to a zone be available in the primary NS immediately.  This could be in rbldnsd itself, where it answers directly, which is what I am leaning on at the moment, or I could forward the data off to another DNS server running perhaps BIND.
> 
> The -c check interval defaults to 1 minute, which will be too slow for my needs.  When I state I need instant access to the zone, I more mean within about 5 seconds.  A user will be putting in some data via a web form.  In the amount of time it takes them to submit the data and then open a command prompt to test it, it should be ready.  Is there any problem with setting -c to something like 5 seconds?  Is there perhaps a mode in which the zone file is always consulted after any change, or a way to tickle the server to reload it rather than use a schedule?
> 
> Could perhaps I -HUP it every time there is a new addition, or would that cause performance issues and deafness?

That's one solution, yes.  There isn't much difference between sending
HUP using -c1.

But keep in mind that if your dataset is large, rbldnsd will have to
reload it each time.  Maybe keeping small additional file that gets
merged into main file from time to time, to have less frequent full
reloads, will help.  It'll be two different datasets for the same
zone.

> I also may have a need to add arbitrary domains into the rbldnsd system.  So while I may have a primary bl.example.com, if a user wants to set up their own zone, which is a subset of bl.example.com, and they have their own domain name, I would like to allow them to add their domain into the system.
> 
> This means I will create the user a data file, but since rbldnsd adds the main zone as a startup parameter, I can see if this service grows, that I will have a very long startup command.  I will also need to reload the server every time I add a new zone.
> 
> Is there some way to chain in a new zone off another, without adding it in as a command to the starting arguments?

No, there's no way to do that.
One reason it's fast is its simiplicitly.

> I seem to recall in the past there was a DNSBL that more or less achieved what I am after, which is the creation and maintenance of your own BL or WL, based on a core of another, but you can bring in your own domain name if you desire, and if you have set up that domain correctly with the right NS's pointing to my system.

Um.  Actually I'm not sure you really want rbldnsd.  Maybe some more
traditional nameserver will do, such as nsd or even powerdns who uses
an sql database for storage.  You'll need to implement the data editing
frontend appropriately.

> Any pointers on this, other solutions, add on's, examples in which others are already doing this, etc, would be most appreciated.

/mjt