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DNS Request problem

Thu, 08/20/2009 - 07:40 — littlegloup

Hello,

I have a problem with DNS request in a precise case.

When I am connecting on HTTPS website, one DNS request is made on my local network for it.
(work network!)
The other DNS requests are made thru proxy.
The HTTP and HTTPS web traffic is send correctly thru the proxy.

I don't know why but it's a little annoying...

Thank for your answer

LG

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Fri, 08/21/2009 - 12:02 — ericjung

Hm, the only thing I can

Hm, the only thing I can suggest is that you ensure "Use SOCKS proxy for DNS lookups" is checked on FoxyProxy's Global Settings tab.

Eric

Fri, 08/21/2009 - 12:54 — littlegloup

Thank you for your answer. I

Thank you for your answer.

I had verify this first and this option is enable.

I don't understand why I have this request!

Fri, 08/21/2009 - 17:14 — ericjung

It's probably a bug in

It's probably a bug in Firefox. DNS lookups in Firefox has notoriously been very difficult to manage.

Fri, 08/21/2009 - 18:26 — littlegloup

have you reproduce this

have you reproduce this problem on your system?

Sun, 08/23/2009 - 18:38 — ericjung

I haven't tried. If you give

I haven't tried. If you give me instructions on how to watch DNS resolution on Ubuntu, I will.

Eric

Sun, 09/27/2009 - 04:36 — fp1400

DNS "leaking" confirmed

I can confirm that FoxyProxy [or at least the API it uses] is failing to direct Firefox to pipe DNS queries through the proxy. Testing has been done using an SSH tunnel with a local SOCKS5 proxy. I have tested remote DNS queries using the regular proxy settings in Firefox and this works fine. When using FoxyProxy, however, DNS lookups are being done locally regardless of the settings used.

You can do this on Ubuntu by using Wireshark. Just run sudo apt-get install wireshark to install it. After launching Wireshark, click the first icon to select an interface to start capturing on [most likely the only one showing packet activity].

Once packet capture has started, type dns in the "Filter:" field and then click [Apply]. This will, as you probably guessed, display only DNS-related traffic. My testing has found that I see DNS queries destined for my local DNS server, even though FoxyProxy is configured to do remote DNS lookups and set to use a particular proxy for all traffic.

When using an SSH tunnel with local SOCKS5 proxy, Wireshark should not see any DNS traffic since it will be encrypted and passed through the tunnel. If using a proxy without SSL then you should probably still see DNS traffic but destined for the remote IP.

Fri, 10/30/2009 - 06:56 — fp1400

Insight

http://housegeekatheart.blogspot.com/2009/10/dns-leak-in-firefox-353-wit...

Quote:

In dynamic switching add-ons, the proxy preference is switched for the http request, but revered to the previous Firefox setting after the request. I would think that the DNS request is made before the correct proxy is selected for the next http request.

This may help to determine where the problem lies. Unfortunately, it doesn't quite explain why some people experience no problems with DNS leaks yet a number of others do.

nb: DNS leaks are still present in Firefox 3.5.4, if anyone was wondering.

Fri, 11/06/2009 - 16:30 — ericjung

Hi, I am aware of the

Hi,

I am aware of the situation and am working on fixing it. In fact, you should be able to route DNS requests to specifc (SOCKS) proxies with patterns, just like you already do with HTTP requests.

Eric

Mon, 11/16/2009 - 05:24 — ericjung

I have a beta for that fixes

I have a beta for that fixes DNS leaking. Is anyone willing to test? Please contact me at eric dot jung at yahoo dot com.

Thank you,
Eric