Re: A Patch for Using Sub-DNS with DNSJava

[Brian W. <bwe...@xb...>]

On Wed, 31 Mar 2004, testttt wrote:

> Hi, Brian and all others,
> 
> In order to use DNSJava in my box without extensively configuring it, I 
> found it's handy if DNSJava can query a sub-DNS before it returns an 
> empty query result. This will work with the *nix resolv library. So, I 
> did some very simple change to jnamed.java:
> 
> 1. a new keyword 'sub-dns' for jnamed.conf. It has a ip and an optional 
> port attribute;
> 2. create a SimpleResolver object for each sub-dns attribute;
> 3. When jnamed is returning response to a query, it checks if the answer 
> section in the response is empty or not;
> 4. If empty, it will try the configured SimpleResolver object to resolve 
> the query;
> 5. break until the response has non-empty answer section, or all sub-dns 
> has been tried;
> 
> So far, it works ok in my machine. I would like to get some comments 
> from Brian or whoever is interested. And ultimately, I'd like this 
> feature in DNSJava or merge my change into DNSJava. Please let me know!

It looks like you're trying to implement something like BIND's forwarders, 
which is a reasonable thing to do.  It's unclear from your code what you 
actually want to do with the queries, though - checking for a non-empty 
answer section isn't right, because if a server returns a valid negative 
answer, you should believe it and not ask anyone else.

The bigger question, though, is why are you using the dnsjava server?  
Its error handling is virtually non-existant, it's not fast, and it 
doesn't do much.  I'd really recommend just running BIND with forwarders.

Brian