[c-nsp] DNS forwarding/proxy

[Florian Prester]

Oliver Boehmer (oboehmer) wrote:
> Check out "Split DNS" feature (very new, 12.4(9)T,
> http://www.cisco.com/en/US/products/ps6441/products_feature_guide09186a0
> 0806bd780.html), which could do what you need, but likely not on your
> platform :-|
>
> What are yoy trying to achieve?
>   
We are restructuring a network, containing about 500 Clients which are 
used to take the default gateway as DNS-Server too.
But within the new network there is a different DNS-Server, which IP is 
unequal to the default GW.

So now I want to redirect the DNS-Traffic so I, or the others do not 
have to alter all the DNS-Server-Entries on the Clients, unfortunately 
they do not use dhcp, yet.

Florian

> 	oli
>
> Florian Prester <mailto:Florian.Prester at rrze.uni-erlangen.de> wrote on
> Tuesday, July 18, 2006 12:19 PM:
>
>   
>> Thanks for your answer, even if it does not sound very good :-(.
>>
>> Is it possible to redirect some traffic by using ACLs?
>> I think I have read something about doing so, but cannot remember
>> where and on what system.
>>
>> Thank you
>> Florian Prester
>>
>>
>> Oliver Boehmer (oboehmer) wrote:
>>     
>>> There is "ip dns server" (don't think it is available on the Cat4500
>>> software releases, but it is in 12.2T/12.3 and later releases in some
>>> advanced feature sets) which turns a Cisco router into a caching DNS
>>> server, it uses the configured "ip name-sever ...." addresses as
>>> forwarders. There is little documentation for this feature (we're
>>> working on it), but next to the "ip dns server", there are also new
>>> keywords for the "ip host ..." command.. 
>>>
>>> 	oli
>>>
>>> Rodney Dunn (rodunn) <> wrote on Thursday, June 29, 2006 4:06 PM:
>>>
>>>
>>>       
>>>> My bad..not enough coffee yet in the morning.
>>>>
>>>> I thought you meant dhcp.
>>>>
>>>> I don't know the answer.
>>>>
>>>> On Thu, Jun 29, 2006 at 04:00:08PM +0200, Florian Prester wrote:
>>>>
>>>>         
>>>>> Rodney Dunn wrote:
>>>>>
>>>>>           
>>>>>> Did you try configuring an "ip helper address x.x.x.x"?
>>>>>>
>>>>>>
>>>>>>             
>>>>> I think an ip helper address is only for Broadcast traffic?? Is it
>>>>> not? I want the router to accept unicast dns requests to its own IP
>>>>> and act as an DNS-Server by asking another DNS-Server (or proxying
>>>>> the request to the other sever).
>>>>>
>>>>> Greetings
>>>>>  Florian
>>>>>
>>>>>           
>>>>>> On Thu, Jun 29, 2006 at 03:11:05PM +0200, Florian Prester wrote:
>>>>>>
>>>>>>
>>>>>>             
>>>>>>> Hi,
>>>>>>>
>>>>>>>  is it possible to configure a Catalyst 4500 (SupIV) to act as a
>>>>>>> DNS Proxy? Or at least to tell it to forward incomming
>>>>>>> dns-requests to a specific DNS-Server?
>>>>>>>
>>>>>>>
>>>>>>> Thanks
>>>>>>>   Florian
>>>>>>>
>>>>>>>
>>>>>>>               
>> --
>> Dipl. Inf. Florian Prester
>> Network Administration
>> Regionales RechenZentrum Erlangen
>> Universitaet Erlangen-Nuernberg
>> Martensstr. 1
>> 91052 Erlangen
>> Germany
>>
>> Tel.: +499131 8527813
>>     


-- 
Dipl. Inf. Florian Prester
Network Administration
Regionales RechenZentrum Erlangen
Universitaet Erlangen-Nuernberg
Martensstr. 1
91052 Erlangen
Germany

Tel.: +499131 8527813