Hello,
this is more like general network question but I hope someone here can help me with that.

Scenerio:
I have a DSL connection with 3 public IP.
As ISP device can handle only one public IP address at at time here is my idea:
- ISP device to be set up as BRIDGE
- the first device on my network site to be SWITCH (2nd layer)
- all servers/devices with public IP will be connected to this SWITCH

For better understanding please have a look at this link with my network design: https://www.dropbox.com/s/hbuzmlz0rpu1bof/baseband.PNG

Question:
Will that work?
- will Server1 and Server2 have access to INTERNET ?
- will hosts behind WiFi (NAT) device will have access to INTERNET ?

Certainly that will work, provided the ISP router is configured appropriately and the ISP is routing all those IP addresses via the router.

Hi cospengle,
I think u you have wrong understading of the problem here.

The ISP router will be reconfigured as BRIDGE, not a router.
The reason why I want to reconfigure it as BRIDGE is because having it as a router will not let me use other public IP addresses (I was sure that this issue was clear in my first post)

It should work, though a lousy modem & switch could cause problems.
However, I suggest that you use a firewall instead of the switch. In your map, you don't have any firewall at all so all firewalling is done on each server - this is not best security practice.

I think you mean you want to set the dsl modem to "passthrough". ISP's don't like to advertise it but I used to set mine to that. The connection point would then move to the next device. The dsl modem becomes a black box. The question them becomes, can you get the next device to authenticate for all three ip's?

Speak to your ISP and run some tests. If you're paying your ISP for multiple IP addresses then they will tell you and ought to support you in some way -- even if it's just to tell you what those IP addresses are.

I have multiple public IP's, I just used multiple individual routers, one for each public IP. I wanted the LAN side segments to be separate for each IP.