[lug] 2 IPs, one DSL

[John Hernandez]

Elyse M. Grasso wrote:

>We have a small linux network that is currently using a single external IP 
>address, which is assigned to the Linksys router. Appropriate ports are then 
>forwarded to the machine which serves as our mail and web server.
>
>We would like to begin using 2 IP addresses while retaining the single DSL 
>into our office. 
>
>Is there a good, reasonably current source online that discusses hardware and 
>software configurations and security considerations for a set-up like this?
>  
>

It would be helpful for us to know more about the current network 
toplogy and what you wish to do with the additional IP address.  Is your 
DSL modem in bridged mode?

I'm going to make an educated guess based on the information you've 
provided so far.  Often people will use additional IP's to create a 
"DMZ" network for public services.  Assuming you have a DSL modem in 
bridged mode with an ethernet connection to your Linksys router, one way 
to build a DMZ is to install an ethernet switch between those two 
devices.  You can then assign pubic addresses to machines connected to 
this new switch.  You'll probably want to enable the host-based firewall 
(among other security precautions) on any DMZ-connected machine, as it 
won't be protected by the Linksys router.