[Opera-Linux] Flushing the DNS cache?

[Herman Robak]

On Tue, 16 Dec 2008 05:46:08 +0100, Daniel Pittman <daniel at rimspace.net> wrote:

> Specifically, when I work inside the network a DNS lookup of
> www.example.com returns a private 192.168.0.0 address, while a DNS
> lookup outside their network returns the routable Internet address.
>
> As far as I can tell Opera is caching these DNS results, even if the
> local DNS resolver, etc, is returning the right stuff, and the only way
> I can find to flush that cache is to restart opera.
>
> Is this the expected behaviour, and if so, is there any way to disable
> the DNS cache in Opera[1], or to flush it automatically or manually?

  Yes, this is the expected behaviour, and so far there is no way
to disable it.  It's a defense against DNS rebinding attacks(*).

We are looking into ways to present information about what is
going on to the user.  Users who are frequently in the situation
you describe either have a serious network problem (which should
be fixed) or an odd environment (which they can work around
explicitly).


*) www.evil.com serves a JavaScript "port scanner", and later
  evil.com's DNS rebinds www.evil.com to 192.168.0.1, which may
  be your DSL router or internal corporate Web server.

-- 
Herman Robak