Re: polipo, dns, and firefox

On Mon, Jan 5, 2009 at 10:19 PM, Daniel Falk
<[email protected]> wrote:
> Alan Jenkins wrote:
>> On Sat, Jan 3, 2009 at 12:06 AM, Eric Radman <[email protected]> wrote:
>>
>>> On 15:06 Fri 02 Jan     , Daniel Falk wrote:
>>>
>>>> Hello,
>>>>
>>>> If I type in a single word in the Firefox address bar, normal behavior
>>>> is for Firefox to automatically complete the url if the domain exists or
>>>> do a search if it doesn't (Google's "I'm Feeling Lucky" by default).  I
>>>> like this feature and have come to rely on it, however Polipo breaks
>>>> it.  It appears to be due to the fact that Polipo won't report this as a
>>>> non-existing domain.  So all I get is a generated page from Polipo
>>>> instead.
>>>>
>>>> Is there a way to achieve the functionality I had previously?  If not,
>>>> could something be put in to fix this?
>>>>
>>> Does Firefox work the same way when using any other HTTP proxy? This
>>> doesn't sound like a feature that a proxy inhibits or supports.
>>>
>>
>> The problem is in Firefox.  I didn't even realise Firefox supported
>> this feature, I've used polipo for so long.
>>
>> The KDE browser Konqueror manages to do it when using polipo.
>> Presumably it picks up on the distinct error code (504) that polipo
>> returns for "host not found".
>>
>> Since you're interested, perhaps you could file a bug against Firefox.
>>
>> Thanks!
>> Alan
>>
> Ok, I went to go file a bug and I found the original bug report (
> https://bugzilla.mozilla.org/show_bug.cgi?id=2875 ).  It is from 1998!
>
> If it hasn't gotten fixed by now, it's not likely to.  But I think the
> main problem is that there is no clear resolution on how to fix it.
> Polipo returns a 504, and other proxies return different codes.

Ah, fair enough.  I just checked the spec (RFC 2616), but it's not
standardized.  504 is appropriate for DNS _timeouts_, but there's no
specific error code for a "host not found" error.  And 504 is also
supposed to be used for normal timeouts.  So I think you're right, you
can't safely distinguish "host not found" by error code.

>  Is it
> impossible for a proxy to return a "host not found" DNS response instead
> of or in addition to an HTTP response?

That is indeed not possible.

> Also: squid allows for a workaround in that you can configure the error
> page.  Thus, a custom error page can give a link to the "I'm Feeling
> Lucky" or whatever.  Polipo doesn't allow for this, does it?

I don't think so.

Have you tried using OpenDns?  They're a free dns service; one of
their features is to catch dns errors.  They certainly do typo
correction for dns.  I _think_ they also provide a search page which
replaces dns errors.  Obviously this is a hack, but maybe it does what
you want.

Alan

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