Discussion:
DNS using TCP only
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Idcrisis
2009-03-11 06:00:28 UTC
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Hi,

I was wondering if there was a way to configure XP to use TCP based DNS
only for its DNS lookups and not use UDP at all.

I have the need to tunnel DNS over SSH and for the life of me I can't get
the UDP->TCP->UDP working.

So I thought that if there was a way to configure XP to use only TCP for
its hosts lookups then my problem is solved.

Thanks for your help,
Id
Todd H.
2009-03-19 07:51:55 UTC
Permalink
Post by Idcrisis
Hi,
I was wondering if there was a way to configure XP to use TCP based
DNS only for its DNS lookups and not use UDP at all.
I have the need to tunnel DNS over SSH and for the life of me I can't
get the UDP->TCP->UDP working.
So I thought that if there was a way to configure XP to use only TCP
for its hosts lookups then my problem is solved.
Thanks for your help,
Id
Two random thoughts come to mind

OpenVPN
Create a local DNS server confirgured for caching only to the remote one.

Not sure you can force XP's resolver to tcp only. Or if you'd really
want to if you could.

comp.protocols.dns.bind might give a better answer.
--
Todd H.
http://www.toddh.net/
Spin
2009-05-04 13:07:58 UTC
Permalink
Post by Todd H.
Two random thoughts come to mind
OpenVPN
Create a local DNS server confirgured for caching only to the remote one.
Not sure you can force XP's resolver to tcp only. Or if you'd really
want to if you could.
comp.protocols.dns.bind might give a better answer.
To idcrisis -

I believe tcp is only for zone transfers when it comes to DNS. UDP is for
query. And that one can't use tcp for query. I could be wrong though.
Jonathan de Boyne Pollard
2010-01-20 17:11:30 UTC
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<blockquote cite="mid:***@mid.individual.net" type="cite">
<blockquote type="cite">
<p>Not sure you can force XP's resolver to tcp only. Or if you'd
really
want to if you could.
</p>
<p><code>comp.protocols.dns.bind</code>&nbsp; might give a better
answer.
</p>
</blockquote>
<p>I believe tcp is only for zone transfers when it comes to DNS.&nbsp;
UDP is for query.&nbsp; And that one can't use tcp for query.&nbsp; I could be
wrong though. </p>
</blockquote>
<p>You are. The protocol falls back from DNS/UDP to DNS/TCP in the
event of large responses that exceed the 512 byte limit, or whatever
limit is negotiated via EDNS0.&nbsp; Moreover some softwares do perform
queries using DNS/TCP in the first instance.&nbsp; (<a
href="http://homepage.ntlworld.com./jonathan.deboynepollard/FGA/dns-shaped-firewall-holes.html#ZoneTransferAdditional">The
only widely used softwares that do this are "zone transfer" clients</a>,
though.)<br>
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