title: TCP: How are the seq / ack numbers generated?
body: <p>I am currently working on a program which sniffs TCP packets being sent and received to and from a particular address. What I am trying to accomplish is replying with custom tailored packets to certain received packets. I've already got the parsing done. I can already generated valid Ethernet, IP, and--for the most part--TCP packets.</p>
  
  <p>The only thing that I cannot figure out is how the seq / ack numbers are determined.</p>
  
  <p>While this may be irrelevant to the problem, the program is written in C++ using WinPCap.  I am asking for any tips, articles, or other resources that may help me.</p>