title: When establish a tcp connection,what if TCP use initial sequence number as a fixed number?
body: <p>I am reading 《Internetworking with TCP/IP》 by Douglas Comer,and when talking about creating a tcp connection ,there is a problem:</p>
  
  <blockquote>
    <p>Suppose an implementation of TCP use
    initial sequence number 1 when it
    creates a connection,Explain how a
    system crash and restart can confuse a
    remote system into believing that the
    old connection remained open.</p>
  </blockquote>
  
  <p>I can't figure out why,please help me,Thanks.</p>