[ih] Broadcast storms [Loss as a congestion signal]

[Brian E Carpenter]

On 23/05/2014 05:26, Louis Mamakos wrote:
...
> Other big fun when a Sun on the LAN had a defective/missing Ethernet
> address ROM.  Reading it yielded all 1 bits.  Someone ARP’s for the Sun’s
> IP address, gets ff:ff:ff:ff:ff:ff (ethernet broadcast address) and now
> sends packets to that destination.  At the time, many hosts helpfully
> defaulted to IP forwarding being turned on.  They’d each receive a
> packet, decide to helpfully forward it along, ARP, get broadcast,
> big melt down.   So more sanity checks (ARP mappings don’t go to
> multicast MAC addresses) and maybe defaulting ip_forwarding on isn’t
> the best decision.

Ah. I wonder if you didn't just debug some of the broadcast storms we
used to get at CERN in the mid-80s, when we first ran our home-made
site-wide Ethernet bridges. Sometimes we just never found the original
source.

   Brian