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EDIT: There is a seemingly similar question already, but it doesn't explore what happens if you don't need to do an ARP request at all, which is what seems to be hindering the communication there.

The title says it all concisely. Is it possible? Does the higher-level constructs like an IP address even matter at this point, now that we know the MAC-address of the receiver, for all intents and purposes it might as well be in our subnet, right?

zombiesauce
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  • I read that thread before coming here. It doesn't explore what happens if you already have the MAC address of the receiver. – zombiesauce May 05 '21 at 16:09
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    If the layer-3 lookup doesn't say "it's local", layer-2 never comes into play. – Ricky May 05 '21 at 16:15
  • If you are using a conventional operating system, such as MacOS, Windows, or Linux, then communication will not work in this case unless you do something "special."

    You mention that the sender "already knows" the receiver MAC address. That would only happen by statically configuring it, or by some other non-standard means. The same would apply to the IP routing table -- you might be able to "fool" it with some custom entries.

    But doing all this may end up breaking normal IP communication. So you'd end up with two host that can only talk with each other and no one else.

     – Ron Trunk May 05 '21 at 16:48
  • You could also forego IP altogether and just rely on MAC addresses. This would require a custom application to do so. – Ron Trunk May 05 '21 at 16:49
  • You could do a lot of things to make that work, e.g. configure a gateway on each host with a local dummy IP address (doesn't need to exist) and then create a static ARP entry for that IP with the MAC of the other host. Each node would think it's using a router but they actually aren't. – Zac67 May 05 '21 at 19:12

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