2 mac address on 1 network

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Silver-0-surfer

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hello...

i have a quick question, if anyone has a quick answer I would appreciate it

So lets say for example I have 2 network cards
card A - mac address - 11:22:33:44:55:66
card B - mac address - 22:33:44:55:66:77

could I spoof card B to make the mac 11:22:33:44:55:66 and then connect that to the same network that that card A is connected to?

will it not connect, give an error?

any help would be appreciated.

thanks
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It's not only possible, it's easy to do with the correct software. The more important question, however, is why?
 
mac spoofing is easy, your network admin won't like you though
 
Depends if routing / switching occurs at the network or data link layer (i.e. depends on the network).
 
Are cards A and B in the same PC, or in different PCs? Also, do you want to have both connected to the network at the same time?

If they're in the same PC, what are you trying to achieve?

If they're in different PCs, and you only want one connected at a time, that'll work (but, as pointed out above, you won't be making friends with your network admin).

If they're in different PCs and you want to have both connected at the same time, it's technically possible, but won't work very well. You'll probably get all the incoming traffic for both PCs going to only one of them, and alternating between the two PCs. Using NAT to share one connection would work better.
 
no network admin, for home use

so you can have multiple pc's with the same mac on one network....interesting

you dont even need to have any special software unless i'm wrong you can configure the card with xp and change locally administered mac address there...

me going to try once i get home:)
 
drs said:
Are cards A and B in the same PC, or in different PCs? Also, do you want to have both connected to the network at the same time?

If they're in the same PC, what are you trying to achieve?

If they're in different PCs, and you only want one connected at a time, that'll work (but, as pointed out above, you won't be making friends with your network admin).

If they're in different PCs and you want to have both connected at the same time, it's technically possible, but won't work very well. You'll probably get all the incoming traffic for both PCs going to only one of them, and alternating between the two PCs. Using NAT to share one connection would work better.
Click to expand...


sorry didn't see the reply

they are not in the same pc but they are going to be connecting to the same network..

thought some problems might occur. will play around with it for a while and see how it turns out.. thanks
 
On the lower layers (layer 2), packets are sent based on MAC address, not IP (because IP is layer 3 - a higher layer), so as DRS says, you'll confuse your switch.

Quote from WNDW ebook:

"Switches
A switch is a device which operates much like a hub, but provides a dedicated
(or switched) connection between ports. Rather than repeating all
traffic on every port, the switch determines which ports are communicating
directly and temporarily connects them together. Switches generally provide
much better performance than hubs, especially on busy networks with many
computers. They are not much more expensive than hubs, and are replacing
them in many situations.

Switches work at the data link layer (the second layer), since they interpret
and act upon the MAC address in the packets they receive. When a packet
arrives at a port on a switch, it makes a note of the source MAC address,
which it associates with that port. It stores this information in an internal MAC
table. The switch then looks up the destination MAC address in its MAC table,
and transmits the packet on the matching port. If the destination MAC
address is not found in the MAC table, the packet is then sent to all of the
connected interfaces. If the destination port matches the incoming port, the
packet is filtered and is not forwarded."

So yes, you'll have issues. Maybe it'll work if you're using an old school hub, but doubtful on a switch.
 
well the reason I asked all this (if any1 cares:) ) is that im trying to set up a secure connection at my moms place.

she has two laptops 1 supports WPA the other not so much only WEP

so I can only use WEP encryption on the AP and we all know that WEP is useless so I wanted to know that if both laptops are connected (with mac filtering enabled) would someone be able to spoof the mac and crack the encryption, which i now know the answer is yes.

so my next plan is this

WPA SKA (shared key association) + mac filtering + only allow ip ranges for 2 pc's ie from 10.0.0.50 to 10.0.0.51 that way only two pcs can connect and they will definitely know if someone else is in? what do you think?

p.s. I have been taken advantage of before so I'm a bit paranoid.
 
If you're going to use WEP, you may as well not use encryption at all. My pocket calculator can crack it.

You could allow only 2 ip addresses, sure. But if you're being paranoid, what's to stop someone breaking into your house, disconnecting one of the PCs and then connecting ?

What adapter do you have that doesn't support WPA ? What OS are you running? I had an adapter that didn't want to work with WPA (only WEP). A driver update didn't work. Curiously, it worked without any hassles in Ubuntu. But when SP3 came out, it started working in XP.

So try update all related software.

Also, it will depend on the particular setup of your router. You should check that out too.
 
Silver-0-surfer said:
well the reason I asked all this (if any1 cares:) ) is that im trying to set up a secure connection at my moms place.

she has two laptops 1 supports WPA the other not so much only WEP

so I can only use WEP encryption on the AP and we all know that WEP is useless so I wanted to know that if both laptops are connected (with mac filtering enabled) would someone be able to spoof the mac and crack the encryption, which i now know the answer is yes.

so my next plan is this

WPA SKA (shared key association) + mac filtering + only allow ip ranges for 2 pc's ie from 10.0.0.50 to 10.0.0.51 that way only two pcs can connect and they will definitely know if someone else is in? what do you think?

p.s. I have been taken advantage of before so I'm a bit paranoid.
Click to expand...

Does your mother have state secrets on that notebooks if you are going thru all this effort to secure her home network?
 
WPA PSK, Mac Filter, IP Range in a Class C network (192.168.xxx.xxx) and you are done. If someone cracks that (it is possible thanks to nVidia SLI) they really want the information.

Oh and btw. 2 same Macs on one Network = not possible.
 
Gixxa said:
WPA PSK, Mac Filter, IP Range in a Class C network (192.168.xxx.xxx) and you are done. If someone cracks that (it is possible thanks to nVidia SLI) they really want the information.

Oh and btw. 2 same Macs on one Network = not possible.
Click to expand...

are you 100% sure because i did it at my house and had no problems with 2 macs on 1 network. only did it to connect but it seemed fine
 
Silver-0-surfer said:
are you 100% sure because i did it at my house and had no problems with 2 macs on 1 network. only did it to connect but it seemed fine
Click to expand...

Put a sniffer on your network and have a look at what happens to the packets/frames...
 
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