How to make ipip tunnel between linux servers?

Question

linux

There are 2 linux servers (debian\centos)
You need to make an ipip or vpn tunnel between them to "transfer" ip from one server to another.
S-server
S1 123.123.123.123
S2 222.222.222.222
It is necessary that the "new ip" connected via the tunnel (222.222.222.222) be displayed on S1 interfaces.
But, so that it would not be displayed as local 192.168.0.3 or 10.10. namely 222...
I read articles: netwild.ru/linuxipip
https://debian.pro/1578
But they require that the donor server has 2 ip (one of which can be transferred). And I need to make such a tunnel (or "transfer" ip), having only one ip-address on the servers.
How can this be implemented? Thanks in advance

Answer 1

This is impossible at least in terms of routing, i.e. how can S1 (123.123.123.123) build a tunnel with S2 (222.222.222.222) if 222.222.222.222 is its own local address?
You can set up a tunnel with gray addresses, for example 10.16.0.1/30 (S1) --> 10.16.0.2/30 (S2), and configure NAT 1to1 translation on S2, in this example 222.222.222.222 in 10.16.0.1, then S1 will receive all requests that go to S2.