[sclug] Nat/Network question

[Roland Turner SCLUG]

On Sat, 2005-12-10 at 23:01 +0000, Hamlesh Motah wrote:

> I currently have a /28 routed to my home ADSL, using one of those Alcatel Speedtouch 510 jobbies, which actually works very well.  Supports the bridging mode required to utilise all the ips, behind that sits an ipcop box which does the NAT/"routing" for the house computers.
> 
> I have recently acquired an Alcatel PCI ADSL card, and I'd like to build a box to replace the router I am currently using, the thinking being to reduce the number of machines I am running.
> 
> Would attempting something like this work?
> 
> ADSL Card > Internet
> Eth0 > Nat'ed interface - for "house computers"
> Eth1 > Bridged interface? (unsure of terminology)

I'm not clear on why you are looking at NAT and bridging at all. Does
your /28 include sufficient address space for all of the PCs at home? Do
you want them all to use public IP addresses? If so, then just set your
machine up as a router (echo 1 >/proc/sys/net/ipv4/ip_forward, or edit
sysctl.conf, or whatever), set both interfaces to have the same address
and make sure that your /28 route points to your LAN rather than to your
ISP.

Akternately, do you want your local PCs to use a mix of public and
RFC1918 addresses, and if so, on one physical network or two?

(I'm taking for granted that you know how to firewall. If you don't talk
about that too before doing this.)

- Raz