Subject: Re: Broadcast and multi-homed routing condition in TCP/IP stack.
To: Andrew Brown <>
From: Charles M. Hannum <>
List: tech-net
Date: 03/07/2001 11:14:28
On Wed, Mar 07, 2001 at 02:13:25PM -0500, Andrew Brown wrote:
> >> Some stacks will allow TCP connection to be established to the broadcast
> >> address configured on any given interface.
> >...
> >It's true that this doesn't catch packets that are sent by Ethernet
> >unicast to the IP broadcast address.  I'm not sure what the prevailing
> >opinion on this is, but we should probably filter such packets.
> i'm of the opinion that something somewhere ought to be checking that
> the layer two address matches the layer three address in type, ie
> unicast, broadcast, multicast, (or anycast).
> this however, would probably be decidedly non-trivial, and rather
> expensive.

Not to mention it would actually break DHCP.