Hi there.

I have two network cards in my machine. From what I've read in the RFCs, it should be possible to provide an internet connection to my girlfriends laptop (M$ lossdoze XP (is my contempt showing?)), by providing her with a seperate IP and routing all packets w. that IP to her machine.

Am I right? What would I google for? Please provide me with a relevant pointer.

Thanks for your consideration.

--Jonas

Jonas, you've clearly read to Smart Questions guide you pointed another user to earlier.

I guess the question is this... do you want her to have a world-resolvable IP? Does your ISP permit multiple IPs/connection? Most cable companies do (or used to anyway), DSL and dial-up did not.

If not, you need Network Address Translation (NAT/IP Forwarding). This is a very common request for linux to perform. You need iptables with NAT and conntrack support. If you want her to obtain an IP via dhcp, you'll also need a DHCP server. I'd be happy to provide more details on this solution if needed.

If they do allow multiple "real" IPs per account, then you could just put the two machines on a switch/hub. Or set up ethernet bridging, if you'd rather she went through your machine.

I have contacted my ISP (I couldn't find answer on their website).

I have found several dhcp servers w. synaptic, but installed none--I can only really test them when the other machine is here.

I have also googled for iptables NAT conntrack, but haven't found a way to determine if my kernel supports it. How do I determine this?

I read a bunch of docs on bridging; among others that it's not recommended to do it in 2.6 kernels (which I use). Comments on this? How do I determine if I can do ethernet bridging?

In case I didn't make it clear, I want to use the internet at the same time as my gf.

Thanks again --Jonas

Could you refer me to the document that suggests bridging is bad with 2.6 kernels? I'm just curious about that.

Anyway, to check if your kernel supports it, look under Device Drivers > Networking Support > Networking Options > Network Packet Filtering > IP Netfilter Configuation in the kernel config. It's well hidden. The options are named CONFIG_IP_NF_* in the kernel .config.

It seems like we're on all the same threads.

I tried looking through my history, by didn't find it. It also seemed weird to me at read-time.

I'm running a stock (i.e. not self-compiled) debian kernel. I found /usr/src/linux -> kernel-source-2.6.8 (which I'm running) and connection tracking is enabled in its config. I can't remember installing any kernel-source nor modifying conntrack, so I can't say how relevant my observation is.

Is there a way to determine whether or not my current kernel supports it, using the image/exectuable only?

And just to make it perfectly clear: both options (NAT/bridge) will allow me to use `teh intarweb' at the same time as the other computer?

I assume you've deduced that my ISP only provides me w. one ethernet plug (otherwise, I'd have tried plugging my gf into the other).

Once again, thx --Jonas

Stock debian kernels provide NAT as modules, IIRC.
NAT will work with all ISPs, and yes, both of you can be online at once. I have my little "lab" of computers all on one DSL connection here.

I've checked with my ISP: I *can* grab two IPs, so I'm probably going to do that. I found an ethernet bridging howto, explaining how to enable it in terms even *I* can understand . Consider that subproblem solved.

Where can I find a guide to NATting?

--Jonas