nanog mailing list archives

Re: Asus wifi AP re-writing DNS packets


From: Neil Hanlon <neil () shrug pw>
Date: Wed, 28 Oct 2020 16:31:43 -0400

And if so, can you set up your own service to remove their iptables rule
after it's been added or otherwise counteract it.

At least temporarily, anyways.

-Neil

On Wed, Oct 28, 2020 at 4:26 PM Ryan Hamel <ryan () rkhtech org> wrote:

I'm curious to know why they would add such a thing, and how you got the
iptables rules from the device. Do these Asus routers provide SSH directly
into the shell?

Ryan
On Oct 28 2020, at 11:33 am, Anurag Bhatia <me () anuragbhatia com> wrote:

Hello,

Wondering anyone from Asus here or anyone who could connect me to the
developers there?

Using Asus RT-AC58U in Access Point(AP) mode and expect it to simply
bridge wired with wireless but seems like it's re-writing DNS packets
source as well as the destination.


   1. DNS port 53 traffic going out, the source is re-written with the
   management IP of the AP on the LAN. So virtually all DNS traffic hits the
   router from the (management) IP of the Asus AP instead of real clients.

   2. If I define DNS as x.x.x.x on DHCP, the Asus AP picks that up and
   re-writes destination to x.x.x.x and hence even if any client uses y.y.y.y,
   the packets are simply re-written.


I see the rule in iptables on Asus AP. All these issues give an idea that
someone created AP mode (besides regular routing mode) and missed to
disable the DNS related NATing features in the AP mode. So far my
discussions with their support have been going quite slow and would greatly
appreciate if someone could connect me to right folks in there so they can
release a firmware fix for it.



Thanks.

--
Anurag Bhatia
anuragbhatia.com



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