I'm trying to set up a new Archer A20 on our network, and I have hit a snag: when trying to point the router to our internal DNS, the interface refuses to save the setting. It displays a message: "DNS server IP address and LAN IP address cannot be in the same subnet. Please enter another one."

The best reason I can come up with for this behavior would be built-in protection from DNS rebinding attacks, which is ordinarily quite a useful feature. But we have control over our internal DNS, so we aren't really worried about this particular type of attack. Moreover, we need to point everything on our network to our DNS to keep our domain controller happy, and to avoid a few other annoying slowdowns and conflicts.

There does not appear to be any option in the administration interface to disable this restriction, and my communications with TP-Link support have been...frustrating.

Have I missed some configuration option to allow pointing to a DNS on the local subnet? Is this feature simply missing from the current firmware? Will the firmware be updated soon?

Thanks,

Daniel