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New Member

Redirect DNS-requests from dial-up users

I have a problem with dns-requests.

Due to an application that was distributed in the early days. People are dialing in to our network with fixed dns-addresses.

I can't find a way to override these addresses during ppp negotiation or with radius-attirbutes but nothing helped.

Now we want to switch dns-servers but it is impossible to reach all of the dailin customers to download another dial application.

Is there a way to configure the as-5300's to send dns-requests bound for the old dns-servers to the new ones with other ip-addresses?

Please help,


Martijn Koopsen

Cisco Employee

Re: Redirect DNS-requests from dial-up users

You can use "async-bootp dns-server x.x.x.x y.y.y.y" command to force the dialin users to negotiate the dns-server ip address that you want.

Here is the url which has a config and commands explanation for that too.

Now you can also use AAA for that as well.

You just need to confiure the correct AV-Paitr for that.

Here is the url for that too.

New Member

Re: Redirect DNS-requests from dial-up users

Thanks for the swift response on my post.

I already have the first option you gave implemented on the as-5300's but the second one is new to me........been looking for it all day.

Will try it tomorrow as soon as i am in the office.

Hope it works.


New Member

Re: Redirect DNS-requests from dial-up users

I tried both the options but unfortunately it does not work.

First of all when i look at a debug ppp negotiation i do not see the dial-up user ask for dns-servers.

Second it looks like only the newer Windows sytems (NT,2K,XP) seem to do this the oter OS-es always ask for dns -servers and if they ask for it they get some from the as-5300.

I hope somebody has some other options.......

New Member

Re: Redirect DNS-requests from dial-up users

Is there somebody who knows anything i can do to redirect the dns-requests?

I am still looking for an answer but i am unable to find it.


Martijn Koopsen

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