Connected to more than one "interface" at a time?

[trek_520]

Ok - this is kind of a dumb question, but I feel compelled to ask.

If I have multiple network cards in my desktop - lets say 1 wireless card and 1 on board lan connection. - can you connect to two networks at the same time?

My scenario - I had to connect to an used network printer that was on the 192.168.0.X network but my desktop was on the 1.1 network. So I went into the properties of the NIC card and change the IPV4 settings to a static address to 192.168.0.5. I could then communicate with the printer at 192.168.0.200. I went in and put it on my network, bla bla bla


I got to thinking... If I am connected to both of these interfaces (or have them active) at the same time do I have access to the resources (like get on the internet on 1.1) on both networks at the same time? Is this true if they are on different networks or subnets? I suppose this application in a home environment is is unnecessary.

Can resources communicate between the networks?

Thanks in advance for any feedback - Sorry if this is a newbie question. Point me to any resources or reading to bring me up to speed. Thanks!

 

[L&LD]

If I am understanding this correctly, yes you can connect to as many networks as you have physical ports for.

Each network will not be shared with the others; the only common bond is the computer that can access any resource on any network it is connected to.

You can setup the computer to 'join' the networks, I'm sure. But I don't know how.

What is your goal? Is it to join the networks together?

 

[azazel1024]

Generally under network properties you select "allow this inferace to be bridged" or something along those lines. Just poke around in network properties.

The only limitation you have is you really, really, really want just one route to the internet. You CAN have more than one, but that gets very complicated.

 

[stevech]

MS windows, and maybe other desktop OSes too, use only one LAN interface at a time. Wired or wireless.

There are standards on how to aggregate the capacity of multiple LAN (NIC) interfaces, but both the PC and the ISP must support such and that's rare.

 

[azazel1024]

I don't think he is asking about bonding connections through an ISP connection.

Resources on both networks are available simultaneously to the machine hosting the NICs connected to both (or all) networks it is connected to. You will need to ensure that the subnet/IP range are different between the networks. You can bridge the connections so that the networks can interconnect.

Multiple interfaces to the same local network resource are only possible through special methods. Bonding is not something done thought the OS (normally). SMB is semi-exception in that SMB3+ (at least on windows) allows SMB Multichannel which does allow multiple interfaces (at the SAME speed) to connect to one resources on the network at once (in effect, if not exactly in practice, bonding the connections).

Link aggregation is still 1:1. No 2:1 or 2:2 or anything allowed, but it does present more than one interface to the same network at once.

 

[sfx2000]

bond's are interesting, but I've very much stayed away from commenting on this, as every situation is unique... and there's been a fair amount of questions.

I create bonded interfaces all the time to different ISP's and ASP's, either for fail-over, round-robin, or biased - but this is typically on a 12 to 24 core XEON based linux box with 32GB RAM or more in a controlled carrier grade data center...

Example here would be Sybase/Syniverse on the ASP level and softlayer/saavis on the ISP level with multiple VPN/MPLS binds.

Like they say on facebook - bond relationships are, erm, complicated...

This doesn't translate well to desktop OS's, even Mac OS X, which has a great network stack, as the applications are very task specific, and rarely carry over as a general case...

one place to start - the Linux Bonding Driver HOWTO -- but even then, you're on your own from there...

 

[trek_520]

I don't think he is asking about bonding connections through an ISP connection.

Resources on both networks are available simultaneously to the machine hosting the NICs connected to both (or all) networks it is connected to. You will need to ensure that the subnet/IP range are different between the networks. You can bridge the connections so that the networks can interconnect.

This is what I was confused and asking about. I guess I did not realize a computer could see the resources different networks at the same time. If both of the networks would happen to have have wan connections how would it choose which one to use?

I suppose it would be much more useful to have different networks setup in a home and have the computers connect to the network that is appropriate. For example - if you had IP cameras that you did not want other people in the home to see you could put them on a different network. Then you could use multiple nics in the PC to connect to them simultaneously correct?

I am talking all theory here - This may not make any sense to setup a network this way.

 

[trek_520]

bond's are interesting, but I've very much stayed away from commenting on this, as every situation is unique... and there's been a fair amount of questions.

I create bonded interfaces all the time to different ISP's and ASP's, either for fail-over, round-robin, or biased - but this is typically on a 12 to 24 core XEON based linux box with 32GB RAM or more in a controlled carrier grade data center...

Example here would be Sybase/Syniverse on the ASP level and softlayer/saavis on the ISP level with multiple VPN/MPLS binds.

Like they say on facebook - bond relationships are, erm, complicated...

This doesn't translate well to desktop OS's, even Mac OS X, which has a great network stack, as the applications are very task specific, and rarely carry over as a general case...

one place to start - the Linux Bonding Driver HOWTO -- but even then, you're on your own from there...

Well - most of what you said was way over my head, but I apprecate your response . So that I can at least follow conceptually in the beginning of your post your are talking about ISP, WAN or enterprise level connectivity for large numbers of users over wide areas? I assume those or implemented for very specific use cases where more bandwidth is needed? I even understand the concept of fail over, but round-robin, and biased are new terms to me.

On the host side - other than bandwidth aggregation (which I am not trying to minimize) I am unclear why one would want to do this. Lastly so I am clear - bonding really does not have anything to do with connecting to multiple networks a the same time - correct?

Thanks all for the education.

 

[azazel1024]

Multiple WAN what you'll want to do is setup only one of the WAN interfaces with a gateway and setup the other one with an empty gateway. You may have to set perferred pathing to the WAN so it'll only go through the one interface. You can also setup the router on one network to block your computer so you are only allowed out through the one network.

Alternately, you can setup bridging so that the one network access the internet through your computer.

PFSense is good for this kind of stuff from what I have heard, to setup multiple networks through one outlet.