[Hampshire] webserver route to another box on an internal LA…

Hi,

At work we have moved office and changed our internet connection from
a single single IP address to a block of fixed IP addresses.
Previously our single IP was NATted
by an IPCop box which routed HTTP traffic on different incoming ports
to different servers. We don't have the IPCop box in our current
network and have less fixed IP addresses than we have boxes we want to
be able to see over the 'net. In particular, at the moment a box we
use as a wiki server is not visible.

So what I'd like to be able to do is to browse to one webserver on
port 80 and have it route wiki requests to a different server which is
on the internal LAN but does not itself have an externally visible IP
address.

I've used URL rewriting before but don't believe that will work
because the target box is not visible to the outside world and (AIUI)
a rewrite rule would cause the user's browser to request the second
address, which would fail - or have I got that wrong?

I've not used VirtualHosts in the past and wondered if that might give
a solution but it looks like that is doing something different. Is
this a case where proxying is appropriate? I've never really got what
proxies do...