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- Why do I see a RST, ACK packet instead of a RST packet?
SYN --> <-- SYN ACK ACK --> In the case of a RST ACK, The device is acknowledging whatever data was sent in the previous packet(s) in the sequence with an ACK and then notifying the sender that the connection has closed with the RST The device is simply combining the two packets into one, just like a SYN ACK
- Why is the last ACK needed in TCP four way termination
As a side note, this also implies A needs to "stay here" after it has sent its ACK to B's FIN: when B retransmits the FIN, if A's gone, B won't get any ACK (and possibly a RST) and so cannot guarantee A knows it has received all data A stays some time in the TIME_WAIT state to ACK such retransmitted FINs
- Window Size and ACK Number - Network Engineering Stack Exchange
Each ACK allows the sender to again send two new segments, before the Window is full again, and the Server is again forced to pause This happens up until Packet# 51, when the Client (Recever) increases the Window Size significantly, allowing the Server (sender) to start transmitting data uninhibited again at least until Packet #175, when
- Why need Ack flag if we already have ack number in TCP
The ACK flag indicates that the Acknowledgment Number field is significant, ie containing a meaningful value When a socket connection has already been established that is nearly always the case, but it isn't while a connection is being established Acknowledgment Number: 32 bits
- NACK vs. ACK? When to use one over the other one?
For instance, segments with only the ACK or RST flag set do not require an ACK Additionally, if delayed ACKs are in use, then there may not be an ACK every segment, however generally this requires that an ACK be sent for every other segment Yet many TCP connections will not use delayed ACKs and will send an ACK for every segment carrying data
- What does TCP DUP ACK mean? - Network Engineering Stack Exchange
So - if you're seeing a few random duplicate ACK's but no (or few) actual retransmissions then it's likely packets arriving out of order If you're seeing a lot more duplicate ACK's followed by actual retransmission then some amount of packet loss is taking place Both situations are, unfortunately, entirely possible on the global Internet
- TCP Handshaking Meaning of RST - networking
I am setting up the enc28j60 ethernet controller as a server, and have script to serve as the client I try to send a SYN,ACK packet from the enc28j60 (an ethernet controller) with my own TCP IP stack in response to the SYN from the client, but I always receive RST instead of ACK The checksum in my SYN,ACK is correct according to Wireshark
- Why does a pure ACK increment the sequence number?
Host2 sends a SYN+ACK segment (seq = ISN(s), ACK = ISN(c)+1, options) back to Host1 Host1 sends the last ACK segment (seq = ISN(c) +1, ACK = ISN(s)+1) to server to complete the handshake But there is no data contained in the 3rd segment, meaning Host1 does not inject more bytes into the communication path What is being sent is the header only
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