Oprano Adult Industry Forums - View Single Post - Do you want Gonzo to post your real name?

2MuchMark · 03-20-2008

First it will be useful to define what MAC addresses are and how they
are normally used.

Definition:
http://en.wikipedia.org/wiki/MAC_address
"Media Access Control address (MAC address) is a unique identifier attached to most forms of networking equipment." Normally a twelve digit hexadecimal number, like: 00-08-74-4C-7F-1D

How it is used:
It's most common use is in the "data link" layer of the OSI model: http://en.wikipedia.org/wiki/OSI_model

When a computer on a network has an IP address it needs to contact it sends out an ARP request to all machines on its network segment (using the broadcast address) and receives an answer from the owner of that address with its mac address. It then stores this in an arp table for later reference. The mac address is then used to send data directly to that computer.
http://en.wikipedia.org/wiki/Address...ution_Protocol

You can view the arp table on a windows XP machine by typing "arp -a" from a command prompt. You can even manipulate the table, though this is not recommended. http://www.mytechsupport.ca/content/view/83/306/

What you will see in your arp table are IP addresses that are on your local network. You will not see any entries for computer beyond your closest router. The reason for this is simple; your computer doesn't care about anythign past that.

All a computer needs to know is how to get to the next router on the way to its final destination (next hop). Once your PC has the mac address of your closest router and hands the data off to it, then it is that next router's job to have the mac address of the next router in line and so on. Each router is only going to keep arp tables with mac addresses of devices that are on the same subnets as they are on.

Remember the way they usually acquire mac addresses is using a broadcast. This will only reach as far as the next router. Routers will not pass on this information. If they did the whole Internet would come to a screeching halt because there would be so many broadcasts that the real data would be choked out. They only need to know how to get to the next hop.
http://en.wikipedia.org/wiki/Broadcast_address

In short, as long as your router is seperated from this server that you are connecting to by at least one other router (which I'm sure that you are) they would not have your mac address in their arp tables. You can see just how many routers are between you by doing a "trace router".
http://support.microsoft.com/kb/162326/EN-US/

First you will see your routers Ip address that is local to your computer, then you will see the address of your local IPS's router, then there will most likely be several other router before finally making to the server you are connecting to.

Each time the data passes through a router the portion of that data that contains the last mac address is pulled out and the current router's is put in. This allows the next router to respond without an arp request to the previous router.

This is a similar discussion:
http://content.ix2.net/arc/t-4333.html
"There is no way to determine the mac address of your computer, once the packets have passed through a router. The mac address is used only on a local network and as a packet leaves your local network, the mac address is
replaced by the mac address of the router. This happens at every router along the route between you and any other site."

Since your computer has an arp table that contains your routers LAN side mac address it is possible that they could send that in the same way they could 2) 3) and 4). But your router is going to have a different mac address for it WAN side, which is the part that you would care about. Your computer will not have the WAN side mac address in its arp table because it is on the "other side" of your router.

All that to say: They only way they could get your router's WAN-side mac address would be have access to a device on your local ISP's network on the same subnet as your router. This is highly improbable. (This all came from http://answers.google.com/answers/threadview?id=765054) by the way).

Anyway,

It appears that I owe MoeTheMan, an apology (Sort of)!

I had said that it was Impossible to detect the MAC address of a machine via the Internet (without a client).
I was RIGHT.

I also said that TCP/IP did not contain Mac address information.
I was WRONG.

MoeTheMan said TCP/IP DID contact Mac information.
He was RIGHT.

However, only the MAC Address information of each hop from one point to the next is known between the devices, but thats it. The original machine does not know the destination's mac address (unless it is 1 hop away such as from a PC to a router), and the destination does not know the original's mac address.

(If all of this info were contained in TCP/IP, the world would explode. So GREG was right!)

MoeTheMan: I will extend a sincere apology to you if you would do the same to me (for at least calling me names). If you don't want to, then thats ok. My apology is out there. For my part, I made a mistake.

03-20-2008	#327
2MuchMark SigWhore Join Date: Jan 2008 Location: Montreal, Canada Posts: 281	Re: Do you want Gonzo to post your real name? First it will be useful to define what MAC addresses are and how they are normally used. Definition: http://en.wikipedia.org/wiki/MAC_address "Media Access Control address (MAC address) is a unique identifier attached to most forms of networking equipment." Normally a twelve digit hexadecimal number, like: 00-08-74-4C-7F-1D How it is used: It's most common use is in the "data link" layer of the OSI model: http://en.wikipedia.org/wiki/OSI_model When a computer on a network has an IP address it needs to contact it sends out an ARP request to all machines on its network segment (using the broadcast address) and receives an answer from the owner of that address with its mac address. It then stores this in an arp table for later reference. The mac address is then used to send data directly to that computer. http://en.wikipedia.org/wiki/Address...ution_Protocol You can view the arp table on a windows XP machine by typing "arp -a" from a command prompt. You can even manipulate the table, though this is not recommended. http://www.mytechsupport.ca/content/view/83/306/ What you will see in your arp table are IP addresses that are on your local network. You will not see any entries for computer beyond your closest router. The reason for this is simple; your computer doesn't care about anythign past that. All a computer needs to know is how to get to the next router on the way to its final destination (next hop). Once your PC has the mac address of your closest router and hands the data off to it, then it is that next router's job to have the mac address of the next router in line and so on. Each router is only going to keep arp tables with mac addresses of devices that are on the same subnets as they are on. Remember the way they usually acquire mac addresses is using a broadcast. This will only reach as far as the next router. Routers will not pass on this information. If they did the whole Internet would come to a screeching halt because there would be so many broadcasts that the real data would be choked out. They only need to know how to get to the next hop. http://en.wikipedia.org/wiki/Broadcast_address In short, as long as your router is seperated from this server that you are connecting to by at least one other router (which I'm sure that you are) they would not have your mac address in their arp tables. You can see just how many routers are between you by doing a "trace router". http://support.microsoft.com/kb/162326/EN-US/ First you will see your routers Ip address that is local to your computer, then you will see the address of your local IPS's router, then there will most likely be several other router before finally making to the server you are connecting to. Each time the data passes through a router the portion of that data that contains the last mac address is pulled out and the current router's is put in. This allows the next router to respond without an arp request to the previous router. This is a similar discussion: http://content.ix2.net/arc/t-4333.html "There is no way to determine the mac address of your computer, once the packets have passed through a router. The mac address is used only on a local network and as a packet leaves your local network, the mac address is replaced by the mac address of the router. This happens at every router along the route between you and any other site." Since your computer has an arp table that contains your routers LAN side mac address it is possible that they could send that in the same way they could 2) 3) and 4). But your router is going to have a different mac address for it WAN side, which is the part that you would care about. Your computer will not have the WAN side mac address in its arp table because it is on the "other side" of your router. All that to say: They only way they could get your router's WAN-side mac address would be have access to a device on your local ISP's network on the same subnet as your router. This is highly improbable. (This all came from http://answers.google.com/answers/threadview?id=765054) by the way). Anyway, It appears that I owe MoeTheMan, an apology (Sort of)! I had said that it was Impossible to detect the MAC address of a machine via the Internet (without a client). I was RIGHT. I also said that TCP/IP did not contain Mac address information. I was WRONG. MoeTheMan said TCP/IP DID contact Mac information. He was RIGHT. However, only the MAC Address information of each hop from one point to the next is known between the devices, but thats it. The original machine does not know the destination's mac address (unless it is 1 hop away such as from a PC to a router), and the destination does not know the original's mac address. (If all of this info were contained in TCP/IP, the world would explode. So GREG was right!) MoeTheMan: I will extend a sincere apology to you if you would do the same to me (for at least calling me names). If you don't want to, then thats ok. My apology is out there. For my part, I made a mistake.