2 Internet connection and one local network

[Techside Security <security@techside.it>]

Hi,
in my company I have to switch to another provider and for a while I
have to maintain both the internet connection.
I have 2 server that is reachable from internet that is natted 1:1 with
local ip.


INTERNET OLD (32 public ip)	INTERNET NEW (32 public ip)
	|			|
	|			|
	-------------------------
	|			|
	|	FIREWALL	|
	|			|
	-------------------------
		|
		|
		LAN (private network)


Now, the firewall nat all the connection from static ip to local ip for
the 2 server (WEB, MAIL) and for the navigation of the client.

public ip 1 -----> FRW  ------> local mail server ip
public ip 2 -----> FRW  ------> local web server ip

client navigation ------> FRW --------> default public ip (! mail,! web)


The problem is that I can't let to be reachable the server from both
internet connection. Now work only for one connection (with iproute2 and
rules) based on the source local ip of the server.

I have tried with MARK, CONNMARK, CONNTRACK but I'm confused about it.
There is a way to make this working ?

All info are very appreciated.
Thanks.