A TCP keep-alive segment carries a sequence number one prior to the beginning of the send window and may carry one byte of "garbage" data. Such a segment causes the remote side to send an acknowledgment.

May 3, 2011 · TCP uses sequence numbers to detect duplication in the case of retransmission, which will also prevent trivial replay attacks. From RFC 793, Section 3.3 - Sequence Numbers: A fundamental notion in the design is that every octet of data sent over a TCP connection has a sequence number.

Learn what are the best practices for TCP sequence number randomization and how to implement it in your network to prevent or mitigate TCP attacks.

Additionally, a 32-bit sequence number and a 32-bit acknowledgment (ACK) number are used for keeping track of missing or out-of-order packets. Flags such as SYN, ACK, and FIN can be set in the header to indicate that the packet has some special meaning in the TCP protocol.

We describe a variety of attacks based on these flaws, including sequence number spoofing, routing attacks, source address spoofing, and authentication attacks. We also present defenses against these attacks, and conclude with a discussion of broad …

TCP is also vulnerable to sequence-number wraparound: arrival of an old duplicates from the same instance of the connection. However, if we take the MSL to be 60 seconds, sequence-number wrap requires sending 2 32 bytes in 60 seconds, which requires a data-transfer rate in excess of 500 Mbps.

We describe a variety of attacks based on these flaws, including sequence number spoofing, routing attacks, source address spoofing, and authentication attacks. We also present defenses against these attacks, and conclude with a discussion of broad-spectrum defenses such as encryption. 1. INTRODUCTION.

A: SRC=C, DST=S, ACK (SNs) -- but how to guess SNs? Where does the adversary get SNs? TCP specification suggested a specific way to choose them. In particular, increment at a ~constant rate: ~250,000 per second. Why so specific? Subtle interactions with reused connections (src/dst port numbers).

A TCP keep-alive segment carries a sequence number one prior to the beginning of the send window and may carry one byte of "garbage" data. Such a segment causes the remote side to send an acknowledgment.

TCP sequence numbers play a crucial role in safeguarding communication against malicious packet injection attacks. They serve as unique identifiers, ensuring data authenticity and preventing...