@Clive_A BTW, one more thing. In LAN-to-LAN mode, L2TP over IPsec, is DPD enabled? If it is how will the routers reconnect?

@HPF OK, I'll have to test if IPSec works. I was surprised to see L2TP/IPSec worked. Hope IPSec works just as well. Thanks for help.

@HPF It's "L2TP over IPsec". I tried IPSec and configure IKE parameters but Windows PC wouldn't connect. If I set up a LAN-to-LAN connection (Europe-China) using two Omada routers can I use "L2TP...

@Clive_A It will not disconnect as long as I work so I don't think it's GFW but DPD. iPhone will disconnect after maybe 5 minutes of inactivity. Windows PC takes longer, maybe as much as 15 minutes....

I'm in China and do Client-to-LAN connections (iPhone and Windows PC) to a ER707-M2 L2TP/IPsec server in Europe. I have to manually reconnect all the time, very annoying. Log says "DPD detection...