Configure Dual WAN with Asus Router

These days WFH, Routers, Wifi, Speed and backup are some of the common words that we are hearing because of covid-19 situations all over the world. People are forced to work from home because of such a volatile situation.

No one knows when the situation will become normal or will it ever become normal?

It is always good to have a backup internet connection. But there are challenges to it like ISP not providing stable internet or more frequent disruptions.

If your work is critical you should definitely have 2 internet connections, one primary and other back up. Since I also have a critical job, I opted for two internet connections. One of them is reimbursed by my company and another one I pay myself.

Following is my setup:

1. I have ACT as primary connection with 300 Mbps and 850 GB FUP and
2. Airtel has back up with 100 Mbps and 150 GB FUP.

Both of them are backed-up with UPS, so when power fluctuation happens, routers don’t restart, the entire purpose is defeated by having two internet connections.

Another Problem?

When one ISP is gone, I manually have to switch to another WIFI SSID on my computer or other devices and when the primary is back, again I have switched back to it because it is fast with 300Mbps.

Solution?

I have Asus RT-AC87U AC2400 which provides this cool DUAL WAN feature, where you can connect two different ISP’s in the same router.

Profit?

1. When one ISP goes down, it automatically failovers to backup ISP
2. When primary is working, then it failsback to primary.

All this happens within seconds which is configurable. There are other cool options as well like load balancing which equally balances the traffic among two ISP’s to give better performance or you can specifically pin some devices like PS4, desktops, TV’s which need more bandwidth to one ISP and other small bandwidth requirement devices to backup ISP.

Lets see how this is done:

1. Login into your router web UI.. probably router.asus.com or http://192.168.1.1
2. Navigate to WAN and then to DUAL WAN as shown in below picture

Here there are many things you can configure. Let start with basic ones.

1. Enable the Dual WAN
2. Now you can select how you want to configure primary connection, it can be wired internet or something else. In my case it is wired internet.
3. Select what is your secondary WAN. I have selected it as Ethernet LAN. You can connect RJ45 cable from LAN port of your backup router to one of LAN port of primary router (i.e Asus router).
4. Need to mention which LAN port you are using for backup, I have mentioned it LAN port 3.
5. Select WAN mode, whether you need have fail over as I mentioned earlier or you need to have load balance where you can select the ratio of queries you want to load balance between primary and back up.
6. Need to select time for failover and whether you need to fail back if primary is again working. I have selected to fail back to primary and failback trigger condition as failure of DNS query resolution for 25 seconds.

Above settings are enough to configure. so if your devices are connected with primary router SSID, when primary ISP is down, you don’t need to switch SSID, the router will automatically make back up connection as primary.

When you navigate back on main page, this is how it looks like.

Primary is connected while secondary is Hot-Standby

If you click on Secondary WAN, you will below details which you can again configure.

Details for Secondary WAN

Was it so easy for me?

Absolutely not ! Home network experiments always screws you up. Couple of things you need to keep in mind.

1. Both of your router might be on 192.168.1.0/24, so when you connect you LAN cable from back-up to Asus router you will get conflict IP warning on main page.
2. It is easy to switch, just go in LAN → DHCP and then update different range there. Like 192.168.2.0/24 for primary router.
3. Keep in mind that this will refresh and assign IP addresses to all connected devices in your network. Most of the devices will automatically take new IP address from router.
4. But my switch got confused and though interestingly devices connected directly with switch were still working but I could not access switch because I hardcoded 192.168.1.x in switch. So I had to reset it, plug in LAN connection and power on again to get new address from router.
5. I have pi-hole running on raspberry-pi which powers DNS querys and ad-blocking at my home. That was also hardcoded in router and in pi-hole application settings. I forgot to change that setting before changing the network to 192.168.2.0/24, now raspberry-pi isn’t accessible by router and it cannot look up DNS queries… that were fun 15 mins, scratching my head :D
6. Sometimes on the main page it might show Cold-standby, that means connection to your back up isn’t working. In that case try to unplug and plugin LAN cable from back up router or Disable/Enable internet connection under secondary settings.

You can check if you are on back up ISP by unplugging primary ISP, after timeout expires it will Hot-stanby will become primary. Check by navigating to whatismyip.com.

There are so many good DUAL WAN router available in the market. One of cool reason to buy is redundancy.

Dual WAN routers in India

I hope this was helpful to you guys.