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What is SYN-ACK packet?
SYN-ACK is a SYN message from local device and ACK of the earlier packet. FIN is used for terminating a connection. TCP handshake process, a client needs to initiate the conversation by requesting a communication session with the Server. In the first step, the client establishes a connection with a server.
What do TCP retransmissions mean?
resending
The TCP retransmission means resending the packets over the network that have been either lost or damaged. Here, retransmission is a mechanism used by protocols such as TCP to provide reliable communication. The networks are unreliable and do not guarantee the delay or the retransmission of the lost or damaged packets.
When do I see TCP retransmission after SYN, ACK?
I see the Syn the Syn,ACK and after Syn, Ack I see a TCP Retransmission of the SYN Flag 2 times and after the 2nd SYN Retransmission I see SYN,ACK Retransmission. After that the TCP Traffic sometimes “flows” again and sometimes it ends with a RST Flag sent from the Client.
How is the TCP / IP maximum retransmission time out determined?
Description: This parameter controls the initial retransmission time-out that is used by TCP on each new connection. It applies to the connection request (SYN) and to the first data segments that is sent on each connection. For example, the value data of “5000 decimal” sets the initial retransmit time to five seconds.
When do two ACK packets have the same ACK number?
Most packet analyzers will indicate a duplicate acknowledgment condition when two ACK packets are detected with the same ACK numbers. How Do These Happen? Sending TCP sockets usually transmit data in a series.
How are retransmissions a symptom of packet loss?
They are a common symptom of packet loss. In most cases, once the sender receives three duplicate acknowledgments, it will immediately retransmit the missing packet instead of waiting for a timer to expire. These are called fast retransmissions.