[e2e] TCP Option Negotiation

Hari Balakrishnan hari at chive.lcs.mit.edu
Thu May 17 08:57:39 PDT 2001

> Alex,
> This seems to be another manifestation of the standard  problem of old
> duplicate packet.   Your scenario is a violation of TCP's "quiet time"
> requirement upon host crash and restart (it's the same host if it has
> the same IP address).  Quiet time is a vital part of TCP's machinery to
> protect against old duplicates.


Not quite.

Unfortunately the statement: "it's the same host if it has the same IP address" 
is increasingly untrue because of dynamic IP address assignment (e.g., via 
DHCP).  This may well be a theoretical problem, but I've observed (in my home, 
from my FreeBSD DHCP server), turning off a laptop and turning another one on, 
and having the latter receive the former's IP!


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