Set a unique DNS address for one Asus RT-AX86U device only.
Set a unique DNS address for one Asus RT-AX86U device only.
You're looking to set up a single connected device on your router using its MAC address. You want all its traffic directed through a custom DNS IP or domain that blocks ads for it. This should be handled in the appropriate settings area. Yes, you'd enter the custom DNS details in both DNS Server 1 and DNS Server 2, enable manual assignment, and select the device's MAC address. Manual assignment acts as a whitelist, routing traffic only through your chosen DNS while blocking others—exactly what you need to avoid affecting future devices.
You might set up a VLAN for that particular device and direct the DNS there. This would impact only the traffic within that VLAN. (I haven’t tried this with ASUS before, but it seems to function)
Choose a fixed IP or manual DHCP setup for the device. From the dropdown, pick the Client Name or MAC address, assign it either its existing IP or an available unused one, and set the desired DNS server (e.g., 192.168.50.254 for PiHole). The Host Name field isn't required but helps with clarity. If you use a self-hosted DNS, point everything there; keep a public DNS as backup if your local one fails.
I'll attempt it, though the DNS server only accepts one input. Typically, DNS uses two IP addresses, but it seems this version only takes a single string. It appears the URL format isn't supporting long strings, possibly truncating them. I've noted that you have two IPs to enter.
For your main router DNS servers, usually two addresses are used (sometimes three). For your fixed IP settings, only one address matters. Enter the IP (76.76.2.2) instead of the hostname in the DNS Server field. DNS converts a hostname (like p2.freedns.controld.com) into an IP address. If DNS fails, using a hostname won’t help. If the DNS server you set for your static IP goes down, your routers will switch to their default servers. Currently, because your router fields are empty, you’re relying on your ISP’s DNS. You might want to switch to a service like CloudFlare (1.1.1.1) or Quad9 (9.9.9.11), which offers DNSSEC and extra security. Unless you know your current DNS provider, consider setting 76.76.2.2 and 76.67.10.2 as your router’s DNS servers so devices automatically use them without manual entry. If you want to avoid certain DNS providers entirely, you can reserve a static IP and override it with Quad9 or CloudFlare.
It seems you might have activated the manual IP configuration by mistake. You should deselect it and try again. It likely worked once it was off.