Hello everyone!
We have approximately 50 MikroTik routers distributed around the country that are set up to connect to a VPN server running on MikroTik router in our main office. Those VPN tunnels are used only for remote management of the clients as many of them are behind NAT - during most of the time there is no traffic going through them.
A couple of months ago we started to gradually migrate from PPTP to L2TP/IpSec, but soon after that we've noticed that some of the clients experience frequent drops of the VPN session while idle and no drops at all if there is an active connection going through the specific VPN tunnel.
Further investigation showed that the affected devices are those connected to the Internet via the mobile 3G/4G/5G network and apparently their traffic is randomly routed by the ISP through different gateways. As a result the VPN server reports "ipsec XXX.XXX.XXX.XXX remote address mismatched" and drops the session.
Can anyone recommend a solution for that issue?
Thanks!