I wanted to create this small thread for sharing my experience on installing Merlin on RT-AX56U and testing the killswitch feature. Hoping this will be useful for someone on the same situation.
I needed to buy an "affordable" ASUS router compatible with Merlin in order to setup an OpenVPN client on the router with the ability to block any traffic as soon as the VPN falls (this is the killswitch feature, which doesn't come in stock ASUS firmware). Found out they were selling this model for around $120 new in Europe, produced in 2021 in China, and decided to get it. It's actually one of the cheapest models that runs Merlin and is still available for sell, so that convinced me to try.
Still, in the moment of double checking the model I found out that there are two versions of RT-AX56U: with 2 antennas (V1) and with 4 antennas (V2 or sometimes called "Chinese version").
Merlin will ONLY work on the V1 model, which is the model with only two antennas. There are some other posts complaining that installing it on V2 either killed the router or didn't work at all - please be careful.
Installing 388.1 on the V1 worked wonders. You shouldn't worry if you had some previous configuration, but as soon as you install Merlin firmware you should make a hard reset before starting to use it so there are no conflicts of config.
As for the killswitch feature, I could not find any reliable information in this forum about how does it work and many people were complaining that it failed for them when testing. I can say the following from my experience after using it for a month:
Hoping this information helps
I needed to buy an "affordable" ASUS router compatible with Merlin in order to setup an OpenVPN client on the router with the ability to block any traffic as soon as the VPN falls (this is the killswitch feature, which doesn't come in stock ASUS firmware). Found out they were selling this model for around $120 new in Europe, produced in 2021 in China, and decided to get it. It's actually one of the cheapest models that runs Merlin and is still available for sell, so that convinced me to try.
Still, in the moment of double checking the model I found out that there are two versions of RT-AX56U: with 2 antennas (V1) and with 4 antennas (V2 or sometimes called "Chinese version").
Merlin will ONLY work on the V1 model, which is the model with only two antennas. There are some other posts complaining that installing it on V2 either killed the router or didn't work at all - please be careful.
Installing 388.1 on the V1 worked wonders. You shouldn't worry if you had some previous configuration, but as soon as you install Merlin firmware you should make a hard reset before starting to use it so there are no conflicts of config.
As for the killswitch feature, I could not find any reliable information in this forum about how does it work and many people were complaining that it failed for them when testing. I can say the following from my experience after using it for a month:
- Have in mind that the killswitch option is ONLY available for OpenVPN client, not for PPTP or L2TP.
- The killswitch will work ONLY IF THE VPN IS TURNED ON (check in the picture the 'Service State' option). Doesn't matter if the router successfully connected to the VPN or not - the killswitch will work only if this option stays turned ON. I will be repetitive, but I have read several complaints in this forum mentioning that it didn't work or that they disabled the VPN for testing this feature -- that's not the way to test it, because if the VPN is set as OFF, then the killswitch will be disabled as well. In my experience, I can say that it has worked like a charm in real scenarios when the VPN or the hosting service where I have my OpenVPN server fell down.
- You may intensify the security by forcing that all devices connected to the network go only through the VPN adding a rule in the VPN Director. For this, first select 'VPN Director (policy rules)' under the 'Redirect Internet traffic through tunnel' (Image 1) and then add the corresponding range (Image 2).
- This is extra, but remember to set the option 'Automatic start at boot time' for the VPN just to avoid forgetting to turn it on.
Hoping this information helps
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