Multiple Connections

Hi,
I want to know how windows manage two network connections
at the same time (on the same pc)?
and is there any difference between network connection types,
like if one is wireless and the other is cable, or both wireless, both
cable, and how i know which one i'm using now?

regards,

Windows has a very simple router inside it. You can view its routing table by typing this in cammond prompt:

[code:1]route print[/code:1]

Just as a router uses its routing table to route packets to the right interface, windows does but in a more simple and limited manner. You can even change the entries in this routing table and see how it behaves. type:

[code:1]route[/code:1]

with no parameters to get help on that. Usually windows picks one interface and places a default route in the routing table to direct all packets --destined for the internet-- to that chosen interface.

Experts here can help you more and correct me if I'm wrong.

thnks,

but still want to know how it make one connection a default
connection!
and how i be sure which one i use now! how choose the connection
i want? can i make both run at same time?

I'll take a stab at this...

There are a bunch of different ways this "CAN" be configured.. but the most simple explaination with no specific configuration is...

With 2 interfaces on the same network Windows makes the first 'interface' to come up the 'default' interface. All traffic should move in and out that interface.

However.. if the interfaces are on Different networks.. some routing entries are needed to specify what traffic goes where.

Might want to let us know what you are trying to do with this info ( load balancing, redundency, download on 1 interface, game on another) . might give us a better chance of telling you what you need.

S0lo and toddwoo are correct. Basically, if you have two cards (or more) connected, you would generally only configure a single default gateway (i.e. on one of the Nics only). This is the case if it was on the same subnet or the two nics are on different subnets. If they are on different subnets and you configure the default gateway on both nics, you will get a load of issues.

The key is the routing table. If for example;

Nic 1 = 195.31.32.1/30
Nic 2 = 10.10.0.1/24

If you had a default gateway on Nic 1, all traffic would be sent to 195.31.32.2 unelss it was in the 10.10.0.0/24 subnet.

Now, if you modify the routing table to then say that 10.0.0.0/8 went to 10.10.0.254, this would then say that all traffic in the 10. range would be internal and then the router 10.10.0.254 routes the traffic accordingly.

I'm trying to point out that it all depends on the routes as to how multiple connects are used.

Obviously this is for traffic leaving the machine, traffic being received will depend on the ip address on the Nic.

Also, its worth pointing out that if you put a default gateway on both the Nic's above, it would cause loads of issues, it would be hit and miss if the traffic actually went out of the correct interface. Obviously, if you routed public traffic through the 10.10.0.1 interface, it would get mixed up.

Hope that makes sense.

Cheers

Wayne

Obviously this is for traffic leaving the machine, traffic being received will depend on the ip address on the Nic.

And if I'm not wrong, for packets recieved, by default windows does NOT reroute packets destined to any IP even if the routing table tells it to do so. Unless windows is explicitly configured to do so say via "Routing and Remote Access" in win server. So by default, packets are either IN or OUT. The same packet never goes IN then OUT.

Hope I'm not missing any thing here.