you are right.. apologies for everyone.
and about the mentioned setup, i have managed everything by myself, both solution are possible
@podilarius thank you, for answer. My question was a little bit tricky, I wanted to know it is posiible to route public network to the same physical segment as LAN. ex server behind firewall has private IP on one interface and public IP on the same interface (ex. virtual interface) with only one physical connection to firewall.
And now, I know it is possible, have done this. It is needed to set static routing to public IP behind firewall via private IP.