router/nat with only one NIC

[James McDonald]

Tim Wunder wrote:

> Is it possible to route internal internet traffic through a server 
> that has only one NIC?
>
> I've only had one PC connected to the internet for quite some time and 
> have it configured to route all internet traffic through squid, 
> squidguard and dansguardian. I want to add a second PC and have its 
> internet traffic routed the same way. The server that runs squid and 
> dansguardian currently has only one NIC. So far, the information I've 
> found on the 'net through googling indicates that I need to have a 
> second NIC in order to do this.
>
> Is there a way to do it without adding a second NIC?
>
> I know... NICs are cheap, just buy a second one. It'll just be a pain 
> to have to pull the server out from where it is, then install and 
> configure a NIC. I'm trying to avoid that.
>
> Thanks,
> Tim
>
You don't need to add a NIC for the server to act as a 
Proxy/Dansguardian box. The clients on the internal network simply need 
to be configured to use it as the proxy and denied direct access to the 
internet at the firewall.

                   
               <SWITCH/HUB>
                /         |              \
<PROXY> <CLIENT> <FIREWALL>------<INTERNET>

Your client machines make a request and receive a reply on the same NIC....

However you do need a switch / hub to put your proxy and clients on the 
same segment.