Logging incoming MAC-addresses

[WoAyumi]

Dear NFOServers,

In my log I can see only the router's mac-address as the incoming mac-address because the router stands between my machine and a client's machine. Is there any possibility to make my machine able to log the incoming mac-addresses of clients' machines?
Thank you.

[Spray]

The only way to get the MAC address of another client would be if they were directly connected to your machine. MAC addresses are used for direct communication between two network devices. As soon as a client connection passes through any HOP (their home router, their ISP's network) that MAC address is dropped as it's no longer required for communication, as then the discussion moves to the next two pieces of networking devices.

[Edge100x]

Spray's absolutely right. MAC addresses are used at the second layer of the networking stack to direct ethernet traffic to the correct physical device. Unless the client device is on the same physical network segment, it can only reach your server by first going through a switch or router, which means that the ethernet frames will always contain that switch/router's MAC address as the source.

[WoAyumi]

What would be the best alternative for me to effectively block an attacker who uses different IP addresses, with the possibilities given?
Thank you, guys!

[Edge100x]

Without knowing the details of the attack, it's difficult to say. If the person is connecting and interacting with a service, such as a game server, you may be able to block by a game-specific identifier such as a SteamID.