justin bengtson wrote:
>the real dilema, and what i can't puzzle out and/or visualize, is how to route
>to a dynamic IP. especially when i only have one NIC in the router. setting
>up a gateway is simple (for me) when all of the IP's are static and i have two
>NICs.
>
>i need to route inside traffic (my desktop, my sister's desktop) to one dynamic
>outside IP (my desktop to the cable modem) using only one NIC in my machine.
>my machine is thus the router, firewall, and gateway as well as my desktop.
>
It sounds like you want to have two usable computers, with a shared
connection to the internet and a firewall of some sort. I think this
sounds perfectly reasonable, except for the part about the router with
one NIC. That kinda undercuts the definition of a router, which would
have to include something to the tune of connecting multiple networks,
shuffling packets between them. You have two networks, your private LAN
and your cable subnet, each network needs an interface, which means you
need two NICs. You then can have a static IP for that
router/firewall/DHCP-server/desktop (maybe something like 192.68.0.1).
This system can serve as the gateway for your sister's machine, and any
others you might want to connect.
OK, there are some weird things you can do with aliasing so that
your single NIC can have more than one ip (and hence it looks like two
interfaces an eth0:1 and eth0:2, even though they're the same physical
card), but that really starts to complicate things, and makes security a
more difficult prospect as well. What you really want is a system
sitting in between the the internet and your private LAN.
There isn't any reason you can't use the machine that's routing
packets for other things as well. It really sounds like you're trying
to do something tricky to avoid the need for two NICs.
Try if you want but my advice is to admit to the fact that you have
two networks at play here, and go dig up another NIC...why make it more
complicated than it has to be?
Kahli
