[Dnsmasq-discuss] Feature Request?

[Jorge Bastos]

Well what i had in mind is when a non-existent dns name is requested.

>From what you said, forgive me if I interpreted it wrong, dnsmasq is already
able to detect that and reply with a customized value?
Am I correct? If so can you post an example for the config?




> -----Original Message-----
> From: Simon Kelley [mailto:simon at thekelleys.org.uk]
> Sent: quarta-feira, 17 de Setembro de 2008 14:37
> To: Jorge Bastos
> Cc: dnsmasq-discuss at lists.thekelleys.org.uk
> Subject: Re: [Dnsmasq-discuss] Feature Request?
> 
> Jorge Bastos wrote:
> > Hi Simon,
> >
> > What can you say about this?
> >
> >
> It rather depends on what you mean by "doesn't respond". The
> possibilities I can think of are
> 
> 1) network error "No route to host" talking to upstream server.
> 2) Upstream server returns NXDOMAIN or NODATA reply.
> 3) Upstream server returns SERVFAIL or REFUSED return codes.
> 4) Upstream server doesn't reply at all.
> 
> 1) is already detected, and results is a REFUSED reply to the original
> requestor, that could be customised fairly easily.
> 
> 2) are legitimate replies and shouldn't be interfered with,
> 3) are arguably also legit replies, but could be substituted.
> 
> 4) Is difficult to even reliably detect. DNS usually uses UDP as a
> transport, the only way to substitute a different reply for no-reply
> from the upstream server is to use a shorter time-out then the original
> requestor. Since the length of that time-out is not known, that's
> difficult to do reliably.
> 
> On top of this, messing with the DNS in this way can have unexpected
> results: it sounds like you're trying to control the web-surfing
> experience, but DNS is not just the web. If having the DNS go down
> results in substituted results rather than errors, you could easily
> find
> the contents of your mail spool delivered to your local webserver or,
> more likely, bounced by it. There's also the problem that the results
> of
> DNS lookups can get cached in surprising places, leading to problems
> after connectivity is restored.
> 
> Cheers,
> 
> Simon.
> 
> 
> 
> 
> 
> 
> 
> 
> >
> > Jorge,
> >
> >
> >
> >
> >
> > From: dnsmasq-discuss-bounces at lists.thekelleys.org.uk
> > [mailto:dnsmasq-discuss-bounces at lists.thekelleys.org.uk] On Behalf Of
> Jorge
> > Bastos
> > Sent: segunda-feira, 15 de Setembro de 2008 17:47
> > To: dnsmasq-discuss at lists.thekelleys.org.uk
> > Subject: RE: [Dnsmasq-discuss] Feature Request?
> >
> >
> >
> > Yap, DNSMasq is much better, that's why i'd like to have this feature
> on it.
> >
> >
> >
> >
> >
> >
> >
> > From: dnsmasq-discuss-bounces at lists.thekelleys.org.uk
> > [mailto:dnsmasq-discuss-bounces at lists.thekelleys.org.uk] On Behalf Of
> Paul
> > Chambers
> > Sent: segunda-feira, 15 de Setembro de 2008 16:52
> > To: dnsmasq-discuss at lists.thekelleys.org.uk
> > Subject: Re: [Dnsmasq-discuss] Feature Request?
> >
> >
> >
> > I'd like to do something vaguely similar, though in my case it's
> sending
> > requests in a particular domain to a given pair of servers, only when
> a vpn
> > is up (e.g. tun0). If the VPN isn't up, those servers are not
> reachable
> > anyhow.
> >
> > I noticed the 'server=/<domain>/<ipaddr>@<interface>' variant in the
> docs,
> > but haven't had the time to investigate how it behaves if the
> interface in
> > question is down.
> >
> > This is also something pdnsd can do, but dnsmasq is a much better
> tool for
> > my needs in just about every respect, and I'd really prefer not to
> have to
> > run both.
> >
> > Paul
> >
> > Jorge Bastos wrote:
> >
> > Hi,
> >
> > Simon, i'd like to ask for a feature if not implemented yet.
> >
> > I've saw in other dns/dns proxy servers, the ability to serve an IP
> when
> > certain DNS host is down/doesn't respond.
> >
> > Is it possible for dnsmasq, to do this, with two parameters, one for
> on/off
> > the feature, and the 2nd to specify the host/IP for the response.
> >
> > With this I could for example, inside my network, redirect all broken
> DNS's
> > to my webserver specifying a host and do a webpage explaining what
> happened.
> >
> >
> >
> > Is this possible?
> >
> >
> >
> > Thanks in advanced,
> >
> > Jorge
> >
> >
> >
> > PS: I saw it here, and it's something that will be very handy for me,
> and
> > I'm sure for other because of dns problems.
> >
> > ---
> >
> > About: pdnsd is a Proxy DNS server for Linux and FreeBSD that is
> designed to
> > cope with unreacheable nameservers (e.g. because the dial-in link is
> not up)
> > in a graceful manner to prevent DNS-dependent applications like
> Netscape
> > from hanging. It has a permanent disk cache and supports parallel
> query and
> > a wide variety of link uptests. It also has the ability to serve some
> local
> > records.
> >
> >
> >
> >
> >
> >
> > ---------------------------------------------------------------------
> ---
> >
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