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Home > Archive > IIS Server Security > November 2004 > DNS response issue
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| Author |
DNS response issue
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| Stephen 2004-11-01, 5:53 pm |
| Hi,
I am new to DNS. I have written a UDPlistener/UDPsender console application.
I am using the followings components.
a cisco switch (almost outdated but still have to use it)
2 computers connected to the Switch (One a server another a client), the
client is removed from the LAN so any request from the client has to go
through the switch and the server.
The server has the console application, that accepts requests on Port 53.
Suppose the client(ip: a,b,c,d) makes a request for google(ip: m,n,o,p)
through the server(w,x,y,z)... no matter what the request is, the response
to the request should be (e,f,g,h).
basically its a redirection.
the problem is, I have a console client that gets the response (e,f,g,h)
when I make a request to the server... but how can I achieve this result
when I open a browser?....
I ran ethereal and it gives me a bunch of hexadecimal characters that seems
to be a part of the request/response protocol.
How do i capture it? the web browser just hangs and after sometime, "could
not open the page" message pops up.
Please advice,
Stephen.
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| Karl Levinson [x y], mvp 2004-11-04, 5:50 pm |
| UDP listener? Do note that some large replies that cannot fit into a UDP DNS
request are then re-sent via TCP. This can cause intermittent problems with
name resolution of some hostnames and not others.
Try using the NSLOOKUP command in Windows 2000, XP, NT and 2003 to
troubleshoot problems with DNS, e.g. to see whether DNS resolution is working
or not.
DNS requests are handled by the OS, so I believe the web browser should not
be any different from any other DNS application.
Ethereal works best when you know what a normal working traffic looks like.
Ethereal should be able to interpret what the hex codes mean in more or less
plain english. If it is not, it could be the DNS responses are not correctly
formed. Try using ethereal on a computer where DNS is working to see what it
should look like.
I still think using DNS server software that supports "DNS Wildcard entries"
might be an option, depending on your needs.
"Stephen" wrote:
> Hi,
>
> I am new to DNS. I have written a UDPlistener/UDPsender console application.
> I am using the followings components.
>
> a cisco switch (almost outdated but still have to use it)
> 2 computers connected to the Switch (One a server another a client), the
> client is removed from the LAN so any request from the client has to go
> through the switch and the server.
>
> The server has the console application, that accepts requests on Port 53.
>
> Suppose the client(ip: a,b,c,d) makes a request for google(ip: m,n,o,p)
> through the server(w,x,y,z)... no matter what the request is, the response
> to the request should be (e,f,g,h).
>
> basically its a redirection.
>
> the problem is, I have a console client that gets the response (e,f,g,h)
> when I make a request to the server... but how can I achieve this result
> when I open a browser?....
> I ran ethereal and it gives me a bunch of hexadecimal characters that seems
> to be a part of the request/response protocol.
>
> How do i capture it? the web browser just hangs and after sometime, "could
> not open the page" message pops up.
>
> Please advice,
> Stephen.
>
>
>
>
>
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