DHCP problem with DUAL WAN

[sonya7819]

Hi,

I have a ASUS RT-AC5300 router with asuswrt-merlin framework installed. It has one internet connection of its own and another router with its own internet connection is connected to it using one of the LAN ports.

There are several devices in the LAN of the second router(non-ASUS). And I want the devices using the ASUS router to be able to connect to those devices.

I set up the DHCP server in the ASUS router to use 192.168.2.1/23 and the DHCP server in the non-ASUS router is using 192.168.1.1/24. And if I add a DUAL-WAN route in the ASUS router, that all devices connecting to 192.168.1.1/24, connects through the secondary WAN, then the connection goes through the non-ASUS router and the devices under ASUS router's LAN can connect to the devices under the non-ASUS router's LAN.

But when using the ASUS router, if I use a mobile app that scans the LAN to detect a HP printer connected to the other router, for example, it doesn't find it because 192.168.1.1/24 doesn't fall under 192.168.2.1/23.

So I tried to set the DHCP server in asus in a way that 192.168.1.1/24 is included in its IP range, but then the DUAL-WAN rule doesn't apply to those IPs anymore because they are in LAN IP range. So the devices under ASUS router's LAN can't connect to the devices under the other router's LAN anymore.

So how do I set up the DHCP server in asus properly so that the devices under the ASUS router's LAN can connect to the devices under the other router's LAN and also the 192.168.1.1/24 subnet used by the other router's DHCP server is included in the asus router's DHCP server's subnet?

 

[ColinTaylor]

So how do I set up the DHCP server in asus properly so that the devices under the ASUS router's LAN can connect to the devices under the other router's LAN and also the 192.168.1.1/24 subnet used by the other router's DHCP server is included in the asus router's DHCP server's subnet?

You can't. This has nothing to do with DHCP (other than if you try to overlap them it will break your network).

The issue is that you have two separate subnets, so everything is working as it is meant to. You've already said that you can connect to devices on the non-Asus LAN without any problem. The only issue you appear to have is with the HP printer app. That presumably works by using broadcast traffic. Broadcast traffic doesn't travel across subnets which is why it can't detect anything on the non-Asus LAN.