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dual wan failover & vpn connection

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Hi everybody,

i have bought an asus router (RT - AC2900), and installed last merlin version (386_12_4).
i'am testing features & and theses reliabilties.

So my router is dualwan (not bridged), so each wan ports have local IP
- primary wan is a 4G connexion on port LAN1
- secondary is ADSL box on port WAN

for my testing case and to get something simple, i have used only one VPN connexion which route all outgoing connection for lan to this VPN connection.

Initial test state:
- all WAN connexion ok
- vpn connection established
- LAN reachable.

Test: poweroff the 4G connexion

expected behaviour:
- ASUS router switch secondary wan (ADSL box)
- vpn connection lost & reconnection
- lan reachable

- asus router switch to secondary wan
- vpn connection is correctly reconnected
- lan not reachable

from the result state i have tested 2 cases
1) if i power up the 4G router, i go back to test initial state (all is working ... after vpn reconnection etc..)
2) if i reboot the asus router (4G router is still power off), then all is working fine on secondary WAN

it seems routing table could be not correctly initialized when switching from an interface WAN to another ?

i don't think the problem is coming from the VPN provider as i have same behaviour with another vpn provider.

i don't know what to provide, but i guess that the test case is easy to reproduce by "specialists"

if somebody has an idea of the problem ?

That is not a router model. Are you talking about the RT-AC86U?

Is this a brand new router?

Did you install RMerlin firmware and then immediately reset your new router to factory defaults?

Did you set up your router by using a backup config file from another router?
i have bought an asus router (RT - AC2900)

Hopefully it was years ago and not now. RT-AC2900 also called RT-AC86U is the router with the most issues reported and approaching End-Of-Life. Test your luck with Dual WAN in Asuswrt(-Merlin), but it may not work* reliably. For your VPN connection someone else may help you.

* - this custom script may make it work better:

@Tech9 & @L&LD
thanks for your replies.

Yes it is a RT-AC86U.

I made a factory reset and After installed directly the Merlin firmware.

I have configured it from scratch.

reliably issue are due to Hardware or Firmware ?
Hope i will have something working ...

Up to now, wifi works fine, only dualWan + VPN is not working correctly.

The other issue is to be able to reach my LAN from internet through my ADSL box whcich is the fallback WAN.

I will try the Dual Wan failover script !!

You have the order wrong.

  • Flash the firmware you want to use, First.
  • Secondly, fully reset it to factory defaults the WPS Button method is recommended.
  • Do not use a saved backup config file.
  • Do not use a previously used USB drive that contains amtm/scripts (unless you first format the USB drive on a PC to NTFS).

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