Hi, You will probably need 2 vpn's, one in each direction. Perhaps one having a lower distance than the other. As unless you try very hard, you won't get a routable IP address on your 4g/3g modem, so it needs to dial out to the other end. If when both ends fail over you still require connectivity, a hosted Mikrotik VPS can be used as mentioned in an earlier reply. ikev2 notionally (and sometimes actually) should stay connected when one ends IP address changes. Regards Roger From: Karl Auer <kauer@nullarbor.com.au> To: MikroTik Public <public@talk.mikrotik.com.au> Date sent: Wed, 09 Oct 2019 17:43:41 +1100 Subject: [MT-AU Public] State of 3G/4G fallback on MikroTik? Send reply to: MikroTik Australia Public List <public@talk.mikrotik.com.au> [ Double-click this line for list subscription options ] We need to quote to a client for two routers capable of running a VPN between two sites - easy, that's a MikroTik. But they want a fallback to 3G/4G so that the site that falls back keeps Internet access AND so that the VPN keeps running. What's the state of MikroTik 3G/4G fallback? Last I looked it seemed very roll-your-own, and supported only a few very specific dongles... Ideally it would work like the (vastly more expensive) Merakis and just fail everything over to the secondary link if the primary fails, where "fail" would be either a ping test or interface down. That said, I'm OK with a solution that needs more work, as long as once done it is set-and-forget. Any pointers? Regards, K. -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~ Karl Auer (kauer@nullarbor.com.au) work +61 2 64957435 http://www.nullarbor.com.au mobile +61 428 957160 GPG fingerprint: 887A DA07 4DCC EE76 B413 27D4 C638 4189 6CF0 D556 Old fingerprint: 8454 EE43 6215 B6DD 1B4D 9D8D 984D 7BA1 7378 A38D _______________________________________________ Public mailing list Public@talk.mikrotik.com.au http://talk.mikrotik.com.au/mailman/listinfo/public_talk.mikrotik.com. au---------------------------- Roger Plant