How to make a VPN so that when switching providers, the connection and ip are saved?

Question

VPN

I trade on the stock exchange from home, so you need a stable connection to the Internet.
The home provider is periodically buggy - it breaks the connection, etc.

I have Keenetic 4G II, with the ability to hold several incoming networks (pppoe, wi-fi, 4g modem) and when the connection is broken on one line, switch traffic to another.

The problem is that when switching providers, the broker, of course, will break the connection, because my ip will change. And you can’t break the connection even for half a second, delays are acceptable, but not breaking the connection. Therefore, I came up with the idea to send all this traffic through vpn, so that the broker sees only 1 vpn ip, and is not embarrassed that my ip has changed.
The QUIK trading terminal on a computer has the ability to use a proxy (although it probably won't be needed?).

Question: Is it possible to implement this? How is this scheme implemented? What kind of special protocol is needed for this?
Encryption and anonymity are not important. It is important to implement just such functionality.

Equipment, if anything, I can buy something else, but keenetic seems to me to be quite functional.

Answer 1

Maybe it's easier to change providers?
When using VPN, the transfer speed will drop, because. traffic will be encrypted and an additional bypass route through the VPN server will be added.
Implementing a VPN is quite simple. The easiest way is to buy ready-made, now it is not difficult. You need to find a VPN operator that provides the type of VPN that your router supports.
But it’s more reliable, in my opinion, to raise the VPN yourself, it’s also not very difficult. To do this, you need to rent a VPS with Linux, set up a suitable VPN server there. Set up a VPN client on the router. In the routing rules of the router, you need to add a route to the broker's addresses through the VPN server. Do not make VPN the default route, because All traffic will go through the VPN. The router must connect the VPN both through the main and backup channels.
At the same time, you do not need to do anything on your computer and in QUIK - everything will be transparent to them.
Choose a VPS operator that has a server in the region where the broker is located, so you can somewhat reduce delays due to VPN. You can find out where the broker is located by geoip (he can lie) or ask the broker.
When you change the communication channel with a VPN router, naturally the same will break. But QUIK will not know about it, there will simply be a delay in transmission until the VPN rises on the backup channel. Of course, if the delay is decent, then in the end QUIK will also terminate the connection. How long the delay should be for QUIK to disconnect the connection can be found out by tests. Perhaps in QUIK there are some settings that regulate break timeouts.

Answer 2

What you want to do at home will not work.
You can only save an IP address if it is a static IPv6 assigned to you. And it is supported by the broker and both of your providers.
The TCP session will be terminated anyway.
Accept, or put the terminal on a VPS from a reliable host.

Answer 3

rent a VPS for a couple of euros / month with Linux and static ipv4
put wireguard (fashionable VPN) on it and configure it as a server
in the config on ifup / ifdown register masquerading (snat) in this very static ipv4. It is from this address that you will connect to the broker.
install the wireguard module on kinetics and configure it as a client.
or maybe it’s easier not to even bother with a kineticist, and put the client at once on all the necessary computers, phones, tablets, microwaves, lighters.
in the client part of the config, specify the networks that are used for access via vpn.
ps if you wish, you can drive ipv6 through VPN, but the wireguard module does not know how kinetics in ipv6 yet. at least in guya it is not possible to configure it
pps I can adjust the configs if interested