Finding MAC Addresses (Computer IDs)

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Lang
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Finding MAC Addresses (Computer IDs)

Post by Lang »

Is there a way in PHP that I can grab MAC Addresses. Some friends and I are creating a game and want to stop the creation of multiple accounts. So in order to do so, as logging IP addresses and trying to match them doesn't always work with users using dial-up, proxies ect.
we'd like to learn how to log MAC Addresses.

First off, is this legal?
Second, is it possible?
Third, how do I do it?

Thanks in advance,
RobertPaul
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Post by RobertPaul »

As far as I know, MAC addresses are only used on LANs. So no, you can't do that over the internet.
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Ambush Commander
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Post by Ambush Commander »

The closest alternative is IP addresses, but they're a bit iffy.
josh
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Post by josh »

I've seen some require a verified email issued by your ISP to signup, and flagging accounts with emails that don't match their white-list of ISP domains
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BDKR
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Post by BDKR »

The reason this can't work is becuase the indiviudals MAC address will not be propogated (to the best of my knowledge) beyond his gateway. You won't even be able to get the MAC address of the outside interface on his Gateway.
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pickle
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Post by pickle »

As far as I know, the MAC address would only be stored on their DHCP host. Or, if they have static IPs, not even there. A MAC address is not transmitted across the Internet.
Real programmers don't comment their code. If it was hard to write, it should be hard to understand.
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BDKR
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Post by BDKR »

pickle wrote:As far as I know, the MAC address would only be stored on their DHCP host. Or, if they have static IPs, not even there. A MAC address is not transmitted across the Internet.
As it turns out, almost every box in the network that has needed to communicate with his is probably storing his MAC address via an arp table. Same goes for switches, which is why they're so much better then hubs in terms of dealing with network congestion.

From a linux command line, type in "arp -n" and you should see a dump of the kernels arp table.

Cheers,
BDKR
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Post by timvw »

BDKR wrote:
pickle wrote:As far as I know, the MAC address would only be stored on their DHCP host. Or, if they have static IPs, not even there. A MAC address is not transmitted across the Internet.
As it turns out, almost every box in the network that has needed to communicate with his is probably storing his MAC address via an arp table. Same goes for switches, which is why they're so much better then hubs in terms of dealing with network congestion.

From a linux command line, type in "arp -n" and you should see a dump of the kernels arp table.
But you don't need to know the mac addresses of hosts in a different ethernetwork..
http://www.erg.abdn.ac.uk/users/gorry/c ... ridge.html
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BDKR
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Post by BDKR »

timvw wrote: But you don't need to know the mac addresses of hosts in a different ethernetwork..
http://www.erg.abdn.ac.uk/users/gorry/c ... ridge.html
Of course, but that's not what we're talking about anyways.
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Post by Roja »

BDKR wrote:
timvw wrote: But you don't need to know the mac addresses of hosts in a different ethernetwork..
http://www.erg.abdn.ac.uk/users/gorry/c ... ridge.html
Of course, but that's not what we're talking about anyways.
Lang wrote:So in order to do so, as logging IP addresses and trying to match them doesn't always work with users using dial-up, proxies ect.
You don't (generally) use a proxy on the same network. The described problem set implies different networks.

MAC addresses are generally only propogated one network wide, so for the original requestor the answer is generally no - he won't be able to capture them.
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