Can I block based on MAC address?
If I block an IP, the attacker can work around the block by taking a new IP or use a proxy. Is it possible to make a ban based on MAC address? I want to block at the webserver level so that unwanted users don't create unnecessary traffic to the site.
Is the MAC address sent as a part of HTTP request?
Are you asking specifically about blocking HTTP requests at the web server? filtering access to a wifi point? other kind of networking? The question is not very clear.
You can block based on the MAC address, but I can't imagine how that would help you. The MAC address would be that of your own router. MAC addresses are a LAN thing, not an Internet thing.