Connect to docker host IP from container

Hello I have trouble that I need to solve.
I IPIP tunnel and binded external IP address to it. eg 91.89.110.2
I have software that also using this ip address from host (kinda postfix)

I run container with network mode bridge. I cannot use host mode because container expose port and I need to run a several containers that is not possible in host mode.
The problem that when I try to connect or ping from container thit IP it doesn’t work actually.
How to make this work?