Public Ip + Private Ip in one Lan..possible?

[outstream]

Hi All,

we currently have a Cisco 871 router which is linked to the local LAN at my work place. We are using NAT-ing on router to resolve internal, private ip addresses to one external (or public) ip address.

The 871 router has 1 - 10/100 ethernet port and 4 - 10/100 ethernet switch ports (layer 2 links).

Our email is currently hosted outside the organization, at an ISP.

Recently, our managers planned to maintain some other servers internally for email etc. We have purchased a pool of 6 public ip addresses. Now the task is given to us to run these servers on internal network with that pool of public ips in parallel with already existing LAN.

The guy at our ISP told us that in order to use those public ip addresses in an internal network, we have to disable NAT-ing on the router.

My question is simple. We have to use 6 servers, we want to keep servers on public ip and other parts of LAN on private ip. public and private ip running in parallel on same whole LAN. how can i achieve this?


Regards & Thanks.

[johnwill]

Well, on a quick look, it doesn't look like that router will support multiple WAN addresses.

You could put a switch in front of the router to utilize those addresses, but the servers would not be on the same network as the devices connected to the LAN side of the router. Of course, since they're exposed to the public Internet, that may not be a bad thing. :)

You could also have two NIC's in the servers, one for a connection to the router, and the other for the connection directly to the outside world on the switch I mentioned. You'd also have to have software firewall capability on all of the directly connected machines to protect your network.