Why can't the server get the client MAC address, like the client IP?

client-server tcp mac-address
stacker picture stacker · May 18, 2010 · Viewed 18.1k times · Source

From what I know, all the MAC addresses that the packet gone through are in the packet. This is because that each packet that goes in a certain path, should also be returned in similar path. So, if the router of the server know about the mac address of the client (all of them), why the server page (like aspx) cannot have this information?

Please, give an explanation. (don't just tell me that I'm wrong).

If I understand it correctly, the client sends a packet that contains it's MAC address. when to packet go through a proxy (like the client router), the proxy's address is added to the packet too. and so on.

Here is a snippet from Wikipedia about the TCP/IP data line layer:
http://en.wikipedia.org/wiki/TCP/IP_model#Data_Link_Layer

The Data Link Layer is used to move packets between the Internet Layer interfaces of two different hosts on the same link. The processes of transmitting and receiving packets on a given link can be controlled both in the software device driver for the network card, as well as on firmware or specialized chipsets. These will perform data link functions such as adding a packet header to prepare it for transmission, then actually transmit the frame over a physical medium. The TCP/IP model includes specifications of translating the network addressing methods used in the Internet Protocol to data link addressing, such as Media Access Control (MAC), however all other aspects below that level are implicitly assumed to exist in the Link Layer, but are not explicitly defined.

Answer

sum1stolemyname picture sum1stolemyname · May 18, 2010

Actually, the MAC-address stored in the packet is changed on every hop of a packet's journey.

MAC is shorthand for Media Access Control, with media refering to the local communication media. While source and destination IP-Addresses remain the same throughout the journey (and are used for long-distance routing decisions), the source and destination MAC-Addresses just indicate the next hop.

Because of this, the MAC-Address stored in packets received by your server should be the MAC address of your point of presence-router, or of the equipment of your provider.

You might want to have a look at the OSI Layer model and encapsulation.

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