ASUS RT-ACRH13 hijacking port 53 (DNS) when in AP mode

[Digitoxin]

• My primary router is an ASUS RT-AC66U running the latest firmware (3.0.0.4.380.7378).
• The DNS in the WAN settings on this router is configured to use Google's DNS servers (8.8.8.8, 8.8.4.4).
• I have one machine on my network that is configured to use OpenDNS instead of Google for DNS.
• I have manually configured this machines DNS settings for OpenDNS.
• The DNS on this machine has been using OpenDNS until I introduced the RT-ACRH13 onto my network.
• Because my primary router is in a closet, I purchased a second router to provide WI-FI throughout the house.
• I completely disabled all WI-FI radios on my primary router. The second router is the exclusive provider of WI-FI in my house.
• The second router is an ASUS RT-ACRH13 running the latest firmware.
• I have configured it in AP (Access Point) mode.
• All WI-FI devices (including the machine mentioned above using OpenDNS) are connecting to this new router.
• The machine on my network that is configured for OpenDNS is no longer using OpenDNS, it is now using whatever DNS settings are configured on my primary router.
• No matter what DNS servers I configure in this machine, it will continue to use my primary routers DNS. I can even configure bogus DNS servers or non-existent IP addresses in my LAN subnet, but the machine will continue to resolve DNS using my primary routers DNS settings.
• I am using https://www.dnsleaktest.com/ to confirm which DNS servers are being used by the machine
• It appears that the ASUS RT-ACRH13 is hijacking all traffic over port 53 and re-routing it to my primary router for DNS resolution.
• I have taken the ASUS RT-ACRH13 offline and switched WI-FI back to the RT-AC66U until I can get this resolved.

Has anyone else experienced this before or can reproduce this. Is this issue limited to this model or ASUS router or will all similar ASUS routers have this issue? I don't want to invest in another router and find out it is doing the same thing.

 

[david1024]

Having same problem, FW 3.0.0.4.380_8375 . My network is configured such that management IPs are on a different subnet than clients... the management interfaces are stopped at the firewall from accessing the internet. So, any clients that associate with the AP (in AP mode) get all their DNS blocked--no matter what I configure the client for, the AP will intercept the request and try to be a proxy DNS server... however, since the management interface cannot access the internet, the router/firewall blocks the request from the router's management IP/MAC. (thus breaking DNS for any clients connected to the AP.) None of my other AP's have this problem (netgear nighthawk, ancient USRobotics, linksys, tomato-on-asus)

The only work-around I've been able to find is to use a hosts file... and that only works for the 30 or so hosts on my network, not a scalable solution for the internet.

I have a case open with Asus tech support, but they just want me to update the FW (and it is current already),,,, so, I'm thinking this AP has broken FW... is there a 3rd party FW for it?