Proxying requests?

[daguej]

What's the best way to proxy DNS requests? For example, in ndns it is simple:

server.on("request", function(req, res) {
    var c_req = client.request(REMOTE_PORT, REMOTE_HOST);
    c_req.on("response", function (c_res) {
        res.send(c_res);
    });
    c_req.send(req);
});

[tjfontaine]

There is not a clean/useful interface for this yet, the proper way is to extend or add a method in lib/client.js that allows you to override the lib/platform.js defined NS on a per query basis.

A possible solution with a tested interface would be to muck with platform.name_servers directly (see my comment in issue #1 about having an interface for this) and define the name server(s) you want to forward to, and then call reslove. This of course doesn't play nice if you're trying to manage a lot of forwarding to disparate servers for different sets of zones.

A lower level solution is to instantiate a Packet (from lib/packet.js) which takes socket (only UDP right now) and rinfo which is {address: port:} style, then you can form the query as you like it and .send(), though to see the response you'll either need to follow the socket example from lib/client.js or lib/server.js or perhaps reuse the existing socket from a separate server instance and coordinate message responses.

[tjfontaine]

Ok, now if you call resolve with 4 parameters, the 3rd can be used to specify an {address:,port:} or merely a string address

resolve('www.google.com', 'A', '8.8.8.8', function (err, results) {})

Does this meet the needs of your implementation?

[abh]

For what it's worth I needed the same functionality (my use case is monitoring DNS servers) and this the 4-argument option works great for me.

[tjfontaine]

One of the "issues" with the 4 argument solution is that it will follow the retry count, and I'm sure there are other things people are going to want to customize. So I think the right thing would be to keep feature parity of the resolver portion and expose the Request object so that they can issue requests and handle cases at their pleasure.

[abh]

Yeah, I didn't say that the 4 argument API is elegant or future-proof, just that it works. :-) I agree that it'd be cleaner to just let you set it on the resolver object; you just have to make sure that only future requests get the new resolver after it's been changed (at least for my use case).

[tjfontaine]

In 21e4316 it's now possible to construct a Request and specify the timeouts, specific server, and transport. You also interact with the standard EventEmitter model, timeout and message being the most interesting, there's also an end I'm considering this finalized. See examples/request.js for a simple use case.

[asbjornenge]

👍 Perhaps include a proxy/forwarding option at the end of the server example?

[cyrusdavid]

Hi, can you provide an example on how "proxy" the requests to Google's DNS?