Anyone setup multihomed networking on WinXP?

[MrsGoof]

Alexi,

I've done this with win2k and 4 nic's. (no bridging)

Do you want to be able to acess that PC from different networks ?

If so then you need to add routes for the appropriate card for that network speciffically. It's the old ASSUME addage, and windows does a lot of that.

You may find you can connect to it, its just the respoces go out on the other card.

[AtW]

I just dropped you a PM with a link to details on what I want to do. Basically I don't want a router - I just have software server (mine) on that box that listens for incoming requests that should come from more than one line, that's why different NICs are used - problem is that I can't reach it from 2nd card from the outside, which is definately routing related.

I am certain I need to add routes, just which ones??!?!

[Daywalker]

Go ahead PM me the info!

[AtW]

I think I did - think I also got what needs to be added to routing table in order to make this %%%%%er work...

[TheMonkey]

Two questions - is the service bound to both card's IP addresses and has windows firewall stuck it's ugly head in?

[AtW]

Looks like the problem boils down to the following:
I have two NICs on which requests from the Internet come from, the source IPs of requests and thus destination IPs for response can be anything.

This means that it is not possible (?) to use subnets for routing apart from 0.0.0.0, which is default gateway:

route add 0.0.0.0 mask 0.0.0.0 xxx.xxx.xxx.xxx metric 20
route add 0.0.0.0 mask 0.0.0.0 yyy.yyy.yyy.yyy metric 10

Problem here is that the route with the smallest metric will be used, so all RESPONSES are attempted to be routed through that interface, but not the interface that requests came on originally. That's why when I try to connect externally I don't get response because it was sent via other card.

This seems to be the only logical explanation, the question is htf to fix it?

[AtW]

MrsGoof suggests that I need NAT router - I think I had it when I used Linux PC based one and it all worked fine, I resent a bit to use whole PC box (space/power) just for routing, anyone can recommend cheap consumer level NAT routers, like Barricade kind of thing.

[snaw]

Just clarifying - you've a box with two nics listening to requests from the internet, and you want to return the traffic out the interface it was recieved on?

Is this box routing/talking to anythign else inside your network or purely responing to requests coming from outside? Might help if you diagram it also to check what you're trying to do and if you need NAT or not.

Lot's of cheap routers that will NAT etc (Netgear etc)

[AtW]

I PMed you link to details.

Basically I have got 1 card with external IP assigned to it, and I have got 2nd line with also external IP but it currently goes through router (SMC Barricade), I think it does not do NAT - NAT if I am right will basically hide source IP by making it local so that routing can work.

This is bull as I hoped the damn thing would know to route response to TCP/IP connection on the same interface.

Can't use multiple default gateways because fking windows would switch from one to another every minute or so effectively disabling the other card.

[snaw]

OK from looking at that route print output you have one legit interface pointing to the internet :82.35.224.xx

And two 'inside' private interfaces pointing inside your network: 192.168.1.xx & 192.168.7.xx

Is this how it's supposed to be?

Assuming one of those two private address is the inside address of a router that is externally facing, and your trying to accept connections on it, then you're going to encounter a problem with your TCP flow - it's coming in via one interface say(The private one) but it's going out your one default interface (The 82.x.x.x), so most likely your TCP flow appears either to your external router or the inititing party as a TCP out of sequence (Either it's getting a syn-ack it's not expecting, or coming back on a different address or it's been NAT'd an the TCP seq is out of whack).

You could I guess give both external interfaces an equal cost metric in which case I it should load balance but I'm not sure exactly how Windows load balances traffic (Per packet, per destination, at all?)

You could put a router in between as MrsGoof suggested and NAT from the two external connections to your one inside address (i.e. one interface on your PC) - but you'll need to look into getting some kind of router that has the capability to have two external connections, not as common as you might think (Or buy an old cisco router off ebay with three NIC's)