At the end of 11.3.1 Old Duplicate Packets, we claimed that if either side in th
ID: 3596736 • Letter: A
Question
At the end of 11.3.1 Old Duplicate Packets, we claimed that if either side in the TFTP protocol changed ports, the old-duplicate problem would not occur.
(a). If the client changes its port number on a subsequent connection, but the server does not, what prevents an old-duplicate data packet sent by the server from being accepted by the new client?
(b). If the server changes its port number on a subsequent connection, but the client does not, what prevents an old-duplicate data packet sent by the server from being accepted by the new client?
Explanation / Answer
a) TCP connection cannot stay open with a changing port numbeer, because a connection is defined by source ip + port and destination ip + port. In this type of protocol, a logical channel is established between the peers before exchanging the data. So, if the port number will be changed , it will tear down the established connection and re-establishes the connection.
b) The thing is, server never change its port number after accepting the connection.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.