[CoLoCo] Multiple Network Interfaces, one card?

Fri Aug 31 15:52:03 BST 2007

It would help to know what your end goal is.  Why do you care which
interface is used?  What other endpoints are you trying to communicate
with?  Are you just playing with understanding interfaces?  Separating
traffic for some particular reason?  Curiosity about routing?  There
are lots and lots of techniques to play with networks and routing and
making up packets etc etc.  But we'll just stay tied up in
nomenclature until we get a "use case" to chew on - a problem to
solve.

-Neal

On Fri, Aug 31, 2007 at 10:39:33AM -0400, Ringo Kamens wrote:
> Ok, so how would I get the system to route a particular programs
> traffic to a particular interface if they both get to the internet.
> One idea would be to run a small socks proxy on localhost and then use
> a proxy wrapper program to direct traffic that way. Would that work?
> Comrade Ringo Kamens
> 
> On 8/31/07, Dave Price <kinaole at gmail.com> wrote:
> > User level program don't talk to an interface, they talk to the
> > protocol stack which routes traffic to the appropriate interface
> > depending on the IP address / or hostname needed.
> >
> > If you have virtual interfaces set up , and a given application sends
> > data to the subnets served by those virtual interfaces, they will be
> > used for that traffic.
> >
> > On 8/30/07, Ringo Kamens <2600denver at gmail.com> wrote:
> > > Thanks for the sample commands. Is there any *simple* way to making a
> > > program use a certain interface? I was thinking about running a
> > > virtual machine that runs all of its traffic through one of the
> > > multiple interfaces.
> > > Thanks,
> > > Comrade Ringo Kamens
> > >
> > > On 8/30/07, Dave Price <kinaole at gmail.com> wrote:
> > > > Won't get you two MAC's but will get you two IP addresses
> > > >
> > > > ifconfig eth0:1  aaa.bbb.ccc.ddd
> > > > ifconfig eth0:2  aaa.bbb.ccc.ddd
> > > >
> > > > as often as you want ... with different IP's  for each virtual interface
> > > >
> > > > you also me need to add a DEFAULT GATEWAY for each new subne that you
> > > > define this way using the route command - assuming there is a gateway
> > > > on the the subnet
> > > >
> > > > As mentioned before, I don't know if virtual IP's are supported on
> > > > WLAN interfaces - never tried that...  the tricky bit would be getting
> > > > the WLAN to associate with an access point on the appropriate IP
> > > > subnet if that was needed .
> > > >
> > > > aloha (and hope this helps),
> > > > dave
> > > >
> > > > On 8/30/07, Ringo Kamens <2600denver at gmail.com> wrote:
> > > > > While it's true that the MAC address is burned into the card, it
> > > > > doesn't mean it isn't changeable. The operating system manages the MAC
> > > > > address and it can be changed at will so I would assume I could have
> > > > > it flip-flop constantly between two interfaces. What commands would I
> > > > > use to make multiple interfaces?
> > > > > Comrade Ringo Kamens
> > > > >
> > > > > On 8/30/07, David Overcash <funnylookinhat at gmail.com> wrote:
> > > > > > That's the problem that I think we failed to explain.  A MAC address is a
> > > > > > unique identifier given to each networking card (whether it be wireless or
> > > > > > wired), and each device is supposed to have only one per port (or antenna if
> > > > > > you are wireless).
> > > > > >
> > > > > > So you can have two different IP addresses, if you have two different cards
> > > > > > to create two interfaces on.
> > > > > >
> > > > > > -David
> > > > > >
> > > > > >
> > > > > > On 8/30/07, Ringo Kamens <2600denver at gmail.com> wrote:
> > > > > > > Sorry for the slow response, I was out camping in the wilderness. I
> > > > > > > mentioned the ethernet card because I'd also be interested in setting
> > > > > > > up two interfaces on that. Can somebody point me in the right
> > > > > > > direction as to how to do this? Also, I don't see why a card couldn't
> > > > > > > send from two MACs. Doesn't the system control that anyways instead of
> > > > > > > the card?
> > > > > > > Comrade Ringo Kamens
> > > > > > >
> > > > > > > On 8/27/07, Michael Robbert <mrobbert at gmail.com> wrote:
> > > > > > > > Why do you need two different MACs? I don't see any reason that you
> > > > > > couldn't
> > > > > > > > multi home with two IPs from a wireless card.
> > > > > > > > I am a little thrown off by your mention of the ethernet card. It
> > > > > > doesn't
> > > > > > > > sound like you intend to include that in the solution of your problem,
> > > > > > but
> > > > > > > > am I misreading your problem description?
> > > > > > > >
> > > > > > > > Mike
> > > > > > > >
> > > > > > > > On 8/26/07, Ringo Kamens < 2600denver at gmail.com> wrote:
> > > > > > > > >
> > > > > > > > > I have a problem I think somebody here may have enough expertise to
> > > > > > > > > solve. I have one wireless card and one ethernet card. What I want to
> > > > > > > > > do is set up two separate network interfaces so that I can have my
> > > > > > > > > wireless card send data from two separate MAC and IP addresses. Is
> > > > > > > > > this possible? Yes, I googled it and the results came up empty. I
> > > > > > > > > would appreciate any help I could get.
> > > > > > > > > Thanks,
> > > > > > > > > Comrade Ringo Kamens
> > > > > > > > >
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> > > > aloha,
> > > > dave
> > > >
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