Re: {Disarmed} Re: Asus wifi AP re-writing DNS packets

2020-11-05 Thread Verdi R-D
I experienced this as well dealing with some soho "routers" such as the
RT-AC1200. I imagine this configuration is something in-common with a lot
of their offerings. The issue was resolved by making sure the primary DHCP
server and the Asus device both pointed to the same DNS server.

On Wed, Nov 4, 2020 at 2:33 PM Tony Wicks  wrote:

> I had a similar discussion with another vendor recently while testing
> their mesh wireless systems. This vendor’s units are actually re-writing
> dhcp requests that clients make to point DNS to the primary mesh unit. This
> even happened when the mesh platform was in pure bridge mode (as opposed to
> router mode). The vendor said this was to make sure their app worked
> reliably. I’d say this sort of behaviour has quietly become common in the
> one app to rule it all world.
>
>
>
>
>
>
>
> *From:* NANOG  *On Behalf Of *Anurag
> Bhatia
> *Sent:* Thursday, 5 November 2020 7:03 am
> *To:* NANOG Mailing List 
> *Subject:* {Disarmed} Re: Asus wifi AP re-writing DNS packets
>
>
>
> Hello
>
>
>
>
>
> An update on this issue:
>
>
>
> Going through (long) Asus support channel, they first agreed that this was
> intentional to make router.asus.com work but did take my request to make
> that optional. They have issued me a test firmware which so far seems to be
> working perfectly with no-rewriting rules. Hoping that it doesn't bring any
> side effects and they eventually put it in their public release after
> testing.
>
>
>
>
>
>
>


Re: {Disarmed} Re: Asus wifi AP re-writing DNS packets

2020-11-04 Thread George Herbert
This is annoying behavior, because unless you are doing something weird
with actually signing DNS or TCP DNS, the router can just inject a fake
response for their one DNS name they need into any UDP DNS stream with a
tiny bit of inspection.  Hijacking all of DNS is the DUMB way to do it.

And either way you go, it should be configuration flaggable on/off.


On Wed, Nov 4, 2020 at 11:34 AM Tony Wicks  wrote:

> I had a similar discussion with another vendor recently while testing
> their mesh wireless systems. This vendor’s units are actually re-writing
> dhcp requests that clients make to point DNS to the primary mesh unit. This
> even happened when the mesh platform was in pure bridge mode (as opposed to
> router mode). The vendor said this was to make sure their app worked
> reliably. I’d say this sort of behaviour has quietly become common in the
> one app to rule it all world.
>
>
>
>
>
>
>
> *From:* NANOG  *On Behalf Of *Anurag
> Bhatia
> *Sent:* Thursday, 5 November 2020 7:03 am
> *To:* NANOG Mailing List 
> *Subject:* {Disarmed} Re: Asus wifi AP re-writing DNS packets
>
>
>
> Hello
>
>
>
>
>
> An update on this issue:
>
>
>
> Going through (long) Asus support channel, they first agreed that this was
> intentional to make router.asus.com work but did take my request to make
> that optional. They have issued me a test firmware which so far seems to be
> working perfectly with no-rewriting rules. Hoping that it doesn't bring any
> side effects and they eventually put it in their public release after
> testing.
>
>
>
>
>
>
>


-- 
-george william herbert
george.herb...@gmail.com


RE: {Disarmed} Re: Asus wifi AP re-writing DNS packets

2020-11-04 Thread Tony Wicks
I had a similar discussion with another vendor recently while testing their 
mesh wireless systems. This vendor’s units are actually re-writing dhcp 
requests that clients make to point DNS to the primary mesh unit. This even 
happened when the mesh platform was in pure bridge mode (as opposed to router 
mode). The vendor said this was to make sure their app worked reliably. I’d say 
this sort of behaviour has quietly become common in the one app to rule it all 
world.

 

 

 

From: NANOG  On Behalf Of Anurag 
Bhatia
Sent: Thursday, 5 November 2020 7:03 am
To: NANOG Mailing List 
Subject: {Disarmed} Re: Asus wifi AP re-writing DNS packets

 

Hello

 

 

An update on this issue: 

 

Going through (long) Asus support channel, they first agreed that this was 
intentional to make router.asus.com <http://router.asus.com>  work but did take 
my request to make that optional. They have issued me a test firmware which so 
far seems to be working perfectly with no-rewriting rules. Hoping that it 
doesn't bring any side effects and they eventually put it in their public 
release after testing. 

 

 

 



Re: Asus wifi AP re-writing DNS packets

2020-11-04 Thread Anurag Bhatia
Hello


An update on this issue:

Going through (long) Asus support channel, they first agreed that this was
intentional to make router.asus.com work but did take my request to make
that optional. They have issued me a test firmware which so far seems to be
working perfectly with no-rewriting rules. Hoping that it doesn't bring any
side effects and they eventually put it in their public release after
testing.



Thanks.

On Mon, Nov 2, 2020 at 10:09 PM Anurag Bhatia  wrote:

> Hi Alarig
>
>
> I tried that but somehow DNS traffic still does not work. I tried adding
> rules in prerouting as well and still no impact.
>
>
> anurag@RT-AC58U:/tmp/home/root# iptables -t nat  -L PREROUTING -v -n
> Chain PREROUTING (policy ACCEPT 25 packets, 3147 bytes)
>  pkts bytes target prot opt in out source
> destination
>   672 46143 ACCEPT udp  --  *  *   0.0.0.0/0
> 0.0.0.0/0udp dpt:53
> 0 0 ACCEPT tcp  --  *  *   0.0.0.0/0
> 0.0.0.0/0tcp dpt:53
> anurag@RT-AC58U:/tmp/home/root# iptables -t nat  -L -v -n
> Chain PREROUTING (policy ACCEPT 63 packets, 10481 bytes)
>  pkts bytes target prot opt in out source
> destination
>   993 68310 ACCEPT udp  --  *  *   0.0.0.0/0
> 0.0.0.0/0udp dpt:53
> 0 0 ACCEPT tcp  --  *  *   0.0.0.0/0
> 0.0.0.0/0tcp dpt:53
>
> Chain INPUT (policy ACCEPT 46 packets, 8909 bytes)
>  pkts bytes target prot opt in out source
> destination
>
> Chain OUTPUT (policy ACCEPT 0 packets, 0 bytes)
>  pkts bytes target prot opt in out source
> destination
>
> Chain POSTROUTING (policy ACCEPT 0 packets, 0 bytes)
>  pkts bytes target prot opt in out source
> destination
> 0 0 ACCEPT tcp  --  *  *   0.0.0.0/0
> 0.0.0.0/0tcp dpt:53
> 0 0 ACCEPT udp  --  *  *   0.0.0.0/0
> 0.0.0.0/0udp dpt:53
> anurag@RT-AC58U:/tmp/home/root#
>
>
>
>
>
> From my client behind Asus Wifi AP:
>
>  dig @1.1.1.1 whoami.akamai.net
>
> ; <<>> DiG 9.10.6 <<>> @1.1.1.1 whoami.akamai.net
> ; (1 server found)
> ;; global options: +cmd
> ;; connection timed out; no servers could be reached
>
>
>
> Whether or not I have these rules, I see no traffic on port 53 when doing
> tcpdump on the core router (in the North of Asus wifi AP). So clearly
> firewall rules are not working.
> Please suggest if you see something wrong here.
>
>
> Also, in meantime, I heard from Asus and their support mentioned that this
> re-writing is intentional and is done so that end users can access device
> on router.asus.com hostname. I requested them to make this feature
> optional so that at least folks like us can disable it. Let's see how that
> goes.
>
>
>
> Thanks.
>
>
> On Thu, Oct 29, 2020 at 3:13 PM Alarig Le Lay 
> wrote:
>
>> On Thu 29 Oct 2020 02:10:25 GMT, Anurag Bhatia wrote:
>> > I tried deleting the rule and it drops the traffic completely. So DNS
>> > resolution stops working and I am unsure why. It's not like default
>> drop or
>> > anything. I can edit the rule and whatever active port 53 related rule
>> is
>> > there works. But I want case of no such rule at all. :-)
>>
>> Did you try to add
>> -t nat -A POSTROUTING -p tcp -m tcp --dport 53 -j ACCEPT
>> -t nat -A POSTROUTING -p udp -m udp --dport 53 -j ACCEPT
>>
>> after the deletion?
>>
>> --
>> Alarig
>>
>
>
> --
> Anurag Bhatia
> anuragbhatia.com
>


-- 
Anurag Bhatia
anuragbhatia.com


Re: Asus wifi AP re-writing DNS packets

2020-11-02 Thread Anurag Bhatia
Hi Alarig


I tried that but somehow DNS traffic still does not work. I tried adding
rules in prerouting as well and still no impact.


anurag@RT-AC58U:/tmp/home/root# iptables -t nat  -L PREROUTING -v -n
Chain PREROUTING (policy ACCEPT 25 packets, 3147 bytes)
 pkts bytes target prot opt in out source
destination
  672 46143 ACCEPT udp  --  *  *   0.0.0.0/0
0.0.0.0/0udp dpt:53
0 0 ACCEPT tcp  --  *  *   0.0.0.0/0
0.0.0.0/0tcp dpt:53
anurag@RT-AC58U:/tmp/home/root# iptables -t nat  -L -v -n
Chain PREROUTING (policy ACCEPT 63 packets, 10481 bytes)
 pkts bytes target prot opt in out source
destination
  993 68310 ACCEPT udp  --  *  *   0.0.0.0/0
0.0.0.0/0udp dpt:53
0 0 ACCEPT tcp  --  *  *   0.0.0.0/0
0.0.0.0/0tcp dpt:53

Chain INPUT (policy ACCEPT 46 packets, 8909 bytes)
 pkts bytes target prot opt in out source
destination

Chain OUTPUT (policy ACCEPT 0 packets, 0 bytes)
 pkts bytes target prot opt in out source
destination

Chain POSTROUTING (policy ACCEPT 0 packets, 0 bytes)
 pkts bytes target prot opt in out source
destination
0 0 ACCEPT tcp  --  *  *   0.0.0.0/0
0.0.0.0/0tcp dpt:53
0 0 ACCEPT udp  --  *  *   0.0.0.0/0
0.0.0.0/0udp dpt:53
anurag@RT-AC58U:/tmp/home/root#





>From my client behind Asus Wifi AP:

 dig @1.1.1.1 whoami.akamai.net

; <<>> DiG 9.10.6 <<>> @1.1.1.1 whoami.akamai.net
; (1 server found)
;; global options: +cmd
;; connection timed out; no servers could be reached



Whether or not I have these rules, I see no traffic on port 53 when doing
tcpdump on the core router (in the North of Asus wifi AP). So clearly
firewall rules are not working.
Please suggest if you see something wrong here.


Also, in meantime, I heard from Asus and their support mentioned that this
re-writing is intentional and is done so that end users can access device
on router.asus.com hostname. I requested them to make this feature optional
so that at least folks like us can disable it. Let's see how that goes.



Thanks.


On Thu, Oct 29, 2020 at 3:13 PM Alarig Le Lay  wrote:

> On Thu 29 Oct 2020 02:10:25 GMT, Anurag Bhatia wrote:
> > I tried deleting the rule and it drops the traffic completely. So DNS
> > resolution stops working and I am unsure why. It's not like default drop
> or
> > anything. I can edit the rule and whatever active port 53 related rule is
> > there works. But I want case of no such rule at all. :-)
>
> Did you try to add
> -t nat -A POSTROUTING -p tcp -m tcp --dport 53 -j ACCEPT
> -t nat -A POSTROUTING -p udp -m udp --dport 53 -j ACCEPT
>
> after the deletion?
>
> --
> Alarig
>


-- 
Anurag Bhatia
anuragbhatia.com


Re: Asus wifi AP re-writing DNS packets

2020-10-29 Thread Alarig Le Lay
On Thu 29 Oct 2020 02:10:25 GMT, Anurag Bhatia wrote:
> I tried deleting the rule and it drops the traffic completely. So DNS
> resolution stops working and I am unsure why. It's not like default drop or
> anything. I can edit the rule and whatever active port 53 related rule is
> there works. But I want case of no such rule at all. :-)

Did you try to add
-t nat -A POSTROUTING -p tcp -m tcp --dport 53 -j ACCEPT
-t nat -A POSTROUTING -p udp -m udp --dport 53 -j ACCEPT

after the deletion?

-- 
Alarig


Re: Asus wifi AP re-writing DNS packets

2020-10-28 Thread William Herrin
On Wed, Oct 28, 2020 at 1:57 PM Anurag Bhatia  wrote:
> No such feature when running in AP mode. AP mode gives options of wireless 
> settings (SSID etc) and IP for management of the device.

I don't know about this case but I've occasionally noticed devices
where you have to put the device into the mode where the feature
config shows up in the UI in order to disable it. The feature itself
acts independent of whether it shows up in the UI.

Does the asus AP have an "nvram" command? That's likely where the
config is stored.

Regards,
Bill Herrin



-- 
Hire me! https://bill.herrin.us/resume/


Re: Asus wifi AP re-writing DNS packets

2020-10-28 Thread Anurag Bhatia
No such feature when running in AP mode. AP mode gives options of wireless
settings (SSID etc) and IP for management of the device.


On Thu, Oct 29, 2020 at 2:17 AM TJ Trout  wrote:

> Have you tried disabling the 'redirect when wan down' feature? I'm
> guessing they hijack the dns to redirect the user to a captive portal "your
> internet is down" error page possibly?
>
> On Wed, Oct 28, 2020 at 1:42 PM Anurag Bhatia  wrote:
>
>> I tried deleting the rule and it drops the traffic completely. So DNS
>> resolution stops working and I am unsure why. It's not like default drop or
>> anything. I can edit the rule and whatever active port 53 related rule is
>> there works. But I want case of no such rule at all. :-)
>>
>>
>> I setup pihole on Intel NUC little while ago and all Pihole gets is 100%
>> of wifi client traffic behind Asus wifi management IP. :-\
>>
>>
>> Plus no matter what DNS I put, queries goes via whatever router gave up
>> when Asus booted up.
>>
>>
>> Here's how creepy it gets:
>>
>> On Rasberry Pi (which is not behind Asus AP but a different switch)
>>
>> anurag@raspberrypi:~ $ dig whoami.akamai.com @1.1.1.1 a +short
>> whoami.akamai.net.
>> 162.158.226.218
>> anurag@raspberrypi:~ $ dig whoami.akamai.com @8.8.8.8 a +short
>> whoami.akamai.net.
>> 172.253.244.3
>> anurag@raspberrypi:~ $ dig whoami.akamai.com @9.9.9.9 a +short
>> whoami.akamai.net.
>> 103.224.242.10
>> anurag@raspberrypi:~ $
>>
>> All normal and good.
>>
>>
>>
>> Now, from the device (which is behind Asus AP):
>>
>>  ~> dig whoami.akamai.net @1.1.1.1 a +short
>> 172.217.34.65
>>
>> ~> dig whoami.akamai.net @8.8.8.8 a +short
>> 172.217.34.65
>>
>> ~> dig whoami.akamai.net @9.9.9.9 a +short
>> 172.217.34.65
>>
>> dig whoami.akamai.net @1.2.3.4 a +short
>> 172.217.34.65
>>
>> dig whoami.akamai.net @5.6.7.8 a +short
>> 172.217.34.65
>>
>>
>> Essentially Asus picked 8.8.8.8 because I put that during the test and
>> rebooted the AP. I will stick with 8.8.8.8 until DHCP lease expires and the
>> new server is provided.
>>
>>
>> On Thu, Oct 29, 2020 at 2:01 AM Neil Hanlon  wrote:
>>
>>> 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  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  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


>>
>> --
>> Anurag Bhatia
>> anuragbhatia.com
>>
>

-- 
Anurag Bhatia
anuragbhatia.com


Re: Asus wifi AP re-writing DNS packets

2020-10-28 Thread TJ Trout
Have you tried disabling the 'redirect when wan down' feature? I'm guessing
they hijack the dns to redirect the user to a captive portal "your internet
is down" error page possibly?

On Wed, Oct 28, 2020 at 1:42 PM Anurag Bhatia  wrote:

> I tried deleting the rule and it drops the traffic completely. So DNS
> resolution stops working and I am unsure why. It's not like default drop or
> anything. I can edit the rule and whatever active port 53 related rule is
> there works. But I want case of no such rule at all. :-)
>
>
> I setup pihole on Intel NUC little while ago and all Pihole gets is 100%
> of wifi client traffic behind Asus wifi management IP. :-\
>
>
> Plus no matter what DNS I put, queries goes via whatever router gave up
> when Asus booted up.
>
>
> Here's how creepy it gets:
>
> On Rasberry Pi (which is not behind Asus AP but a different switch)
>
> anurag@raspberrypi:~ $ dig whoami.akamai.com @1.1.1.1 a +short
> whoami.akamai.net.
> 162.158.226.218
> anurag@raspberrypi:~ $ dig whoami.akamai.com @8.8.8.8 a +short
> whoami.akamai.net.
> 172.253.244.3
> anurag@raspberrypi:~ $ dig whoami.akamai.com @9.9.9.9 a +short
> whoami.akamai.net.
> 103.224.242.10
> anurag@raspberrypi:~ $
>
> All normal and good.
>
>
>
> Now, from the device (which is behind Asus AP):
>
>  ~> dig whoami.akamai.net @1.1.1.1 a +short
> 172.217.34.65
>
> ~> dig whoami.akamai.net @8.8.8.8 a +short
> 172.217.34.65
>
> ~> dig whoami.akamai.net @9.9.9.9 a +short
> 172.217.34.65
>
> dig whoami.akamai.net @1.2.3.4 a +short
> 172.217.34.65
>
> dig whoami.akamai.net @5.6.7.8 a +short
> 172.217.34.65
>
>
> Essentially Asus picked 8.8.8.8 because I put that during the test and
> rebooted the AP. I will stick with 8.8.8.8 until DHCP lease expires and the
> new server is provided.
>
>
> On Thu, Oct 29, 2020 at 2:01 AM Neil Hanlon  wrote:
>
>> 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  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  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
>>>
>>>
>
> --
> Anurag Bhatia
> anuragbhatia.com
>


Re: Asus wifi AP re-writing DNS packets

2020-10-28 Thread Anurag Bhatia
I tried deleting the rule and it drops the traffic completely. So DNS
resolution stops working and I am unsure why. It's not like default drop or
anything. I can edit the rule and whatever active port 53 related rule is
there works. But I want case of no such rule at all. :-)


I setup pihole on Intel NUC little while ago and all Pihole gets is 100% of
wifi client traffic behind Asus wifi management IP. :-\


Plus no matter what DNS I put, queries goes via whatever router gave up
when Asus booted up.


Here's how creepy it gets:

On Rasberry Pi (which is not behind Asus AP but a different switch)

anurag@raspberrypi:~ $ dig whoami.akamai.com @1.1.1.1 a +short
whoami.akamai.net.
162.158.226.218
anurag@raspberrypi:~ $ dig whoami.akamai.com @8.8.8.8 a +short
whoami.akamai.net.
172.253.244.3
anurag@raspberrypi:~ $ dig whoami.akamai.com @9.9.9.9 a +short
whoami.akamai.net.
103.224.242.10
anurag@raspberrypi:~ $

All normal and good.



Now, from the device (which is behind Asus AP):

 ~> dig whoami.akamai.net @1.1.1.1 a +short
172.217.34.65

~> dig whoami.akamai.net @8.8.8.8 a +short
172.217.34.65

~> dig whoami.akamai.net @9.9.9.9 a +short
172.217.34.65

dig whoami.akamai.net @1.2.3.4 a +short
172.217.34.65

dig whoami.akamai.net @5.6.7.8 a +short
172.217.34.65


Essentially Asus picked 8.8.8.8 because I put that during the test and
rebooted the AP. I will stick with 8.8.8.8 until DHCP lease expires and the
new server is provided.


On Thu, Oct 29, 2020 at 2:01 AM Neil Hanlon  wrote:

> 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  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  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
>>
>>

-- 
Anurag Bhatia
anuragbhatia.com


Re: Asus wifi AP re-writing DNS packets

2020-10-28 Thread Neil Hanlon
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  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  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
>
>


Re: Asus wifi AP re-writing DNS packets

2020-10-28 Thread Ryan Hamel
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  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.
>
> 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.
> 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 (http://anuragbhatia.com)
>
>
>
>
>
>
>



Asus wifi AP re-writing DNS packets

2020-10-28 Thread Anurag Bhatia
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