PHP: ARP?? Replying to an ARP Request

Question

I know this may be an impossible question, since we are dealing with two different layers of the network, but is it possible to send a reply to an ARP request using PHP sockets?

If so how....such as What port and ip address would you connect the socket to? Again, I understand that arp doesn't use a port number...at least not that I can tell.

I want to do it in PHP, but for those that are going to question my intentions, it is ultimately for a program I am writing for a some piece of hardware. It seems that as though the NIC does not reply to ARP requests, so I want to generate the response manually.

Basically, the only sort of functions that would get me close are socket functions. UDP and TCP.

Oh, I forgot....if Arp is not possible with sockets, is it possible that when I broadcast an "A" record for my hostname, that I can give my MAC address to the router in some sort of dns answer, so the router can respond to arp requests for the hardware's ip address.

Answer 1

ARP runs on the link layer, sockets run on IP. If your host does not respond to ARP requests, it can never correctly receive TCP or UDP packets. You need to implement ARP in the operating system or network stack. It is not possible nor desirable to do so in PHP.

Answer 2

As Sjoerd says: no way through the 'normal' channels as ARP isn't even IP. But if you can call libpcap from PHP, you can use it to sniff ARP requests and also inject replies.

Reading your edits: DNS also won't help as it manages IP addresses, not MAC ones.