title: Most efficient way to manipulate ISN numbers in TCP headers
body: <p>I am currently trying to write a program that will be able to create stable a TCP connection and have complete control over the ISN numbers. I've been writing in C and I am at a point where my very limited knowledge has reached its limits and I was wondering if there's a better way of doing it. </p>
  
  <p>What I tried was building the headers manually, using raw sockets to send and recieve the packets without the kernel interfering, which is a challenge. </p>
  
  <p>So regardless of language, what do you reckon is the most efficient and easiest way of manipulating the ISN? </p>