DNS using TCP only

  • Thread starter Thread starter Idcrisis
  • Start date Start date
I

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
 
Idcrisis said:
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
Click to expand...

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. said:
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.
Click to expand...

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.
 
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.



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.



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.  Moreover some softwares do perform queries using DNS/TCP in the first instance.  (The only widely used softwares that do this are "zone transfer" clients, though.)
 
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