Maurice Tutor

(5)

$15/per page/Negotiable

About Maurice Tutor

Levels Tought:
Elementary,Middle School,High School,College,University,PHD

Expertise:
Algebra,Applied Sciences See all
Algebra,Applied Sciences,Biology,Calculus,Chemistry,Economics,English,Essay writing,Geography,Geology,Health & Medical,Physics,Science Hide all
Teaching Since: May 2017
Last Sign in: 398 Weeks Ago, 6 Days Ago
Questions Answered: 66690
Tutorials Posted: 66688

Education

  • MCS,PHD
    Argosy University/ Phoniex University/
    Nov-2005 - Oct-2011

Experience

  • Professor
    Phoniex University
    Oct-2001 - Nov-2016

Category > Computer Science Posted 16 Jul 2017 My Price 8.00

eavesdrop on ISNA

If a packet arrives at host A with B’s source address, it could just as easily have been forged by any third host C. If, however, A accepts a TCP connection from B, then during the three-way handshake A sent ISNA to B’s address and received an acknowledgment of it. If C is not located so as to be able to eavesdrop on ISNA, then it might seem that C could not have forged B’s response. However, the algorithm for choosing ISNA does give other unrelated hosts a fair chance of guessing it. Specifically, A selects ISNA based on a clock value at the time of connection. Request for Comments 793 specifies that this clock value be incremented every 4 μs; common Berkeley implementations once simplified this to incrementing by 250,000 (or 256,000) once per second.

(a) Given this simplified increment-once-per-second implementation, explain how an arbitrary host C could masquerade as B in at least the opening of a TCP connection. You may assume that B does not respond to SYN + ACK packets A is tricked into sending to it.

(b) Assuming real RTTs can be estimated to within 40 ms, about how many tries would you expect it to take to implement the strategy of part (a) with the un simplified “increment every 4 μs” TCP implementation?

Answers

Maurice Tutor
(5)
Status NEW Posted 16 Jul 2017 09:07 AM My Price 8.00

Hel-----------lo -----------Sir-----------/Ma-----------dam----------- -----------Th-----------ank----------- Yo-----------u f-----------or -----------usi-----------ng -----------our----------- we-----------bsi-----------te -----------and----------- ac-----------qui-----------sit-----------ion----------- of----------- my----------- po-----------ste-----------d s-----------olu-----------tio-----------n. -----------Ple-----------ase----------- pi-----------ng -----------me -----------on -----------cha-----------t I----------- am----------- on-----------lin-----------e o-----------r i-----------nbo-----------x m-----------e a----------- me-----------ssa-----------ge -----------I w-----------ill-----------

Not Rated(0)