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3

The MSS is sent in the handshake, and it is the maximum size of a segment that the side sending it will receive. The window is sent in all the segments, and the sender of it is telling the other side how much data it will accept from the other side, even in multiple segments. The window size is constantly adjusted, based on what the receiver of the data can ...


0

The timers and sequence numbers are for the reliability that TCP gives, not really anything to do with security. See RFC 793, Transmission Control Protocol: When the TCP transmits a segment containing data, it puts a copy on a retransmission queue and starts a timer; when the acknowledgment for that data is received, the segment is deleted from the queue. ...


0

Ping on Windows & Linux systems by default use ICMP. A ping Request will be Type 8 & Code 0 A ping Reply will be Type 0 & Code 0 There are other utilities you can use to run a ping like test for TCP/UDP. A common quick test for seeing if a TCP port is open is using the telnet client on Windows. Nmap is a third party utility you can use on Windows ...


0

Configure filters in layer3 devices with specific service ports and check for traffic . We should able to see traffic when Configured filters with specific service ports .


-1

The server will simple reset the syn packet which is re-send by client and consider as duplicate packet . Basically as TCP is reliable protocol post TCP handshake is successfully only actually application data is transferred . Client --------------- Server .. Client send syn packet Server response back with SYN-ACK 3)Again post receving SYN -ACK from ...


1

It's completely normal to send data with the second ACK already. It's the client (socket initiator) sending the first part of its request (or initiating the SSL handshake). Since it's already received an ACK from the server, there's nothing prohibiting it. For details, see RFC 793 Figure 6 - since the intiator has received the SYN/ACK sequence, the socket is ...


2

We know that port 80 is just a welcoming port, when the web server reveives a http request, it create a new connection port(let's say 5000) No, that's not true. Port 80 is the destination port that all packets send to the web server's web service are sent to. So my understanding is, the initial address of the client uses to send packet to the the server's ...


9

We know that port 80 is just a welcoming port, when the web server reveives a http request, it create a new connection port(let's say 5000) That's not correct for the HTTP protocol. Some protocols, namely FTP, work similarly to that, but not HTTP. So my understanding is, the initial address of the client uses to send packet to the the server's ip address + ...


6

We know that port 80 is just a welcoming port, when the web server reveives a http request, it create a new connection port(let's say 5000) This seems to be the source of your misunderstanding. This is not accurate. The client picks a random high-number port as the source port when making the connection. This happens before the TCP SYN packet is sent, so it ...


3

No ,! Server destination port never changes its remain same in your scenario it's http port 80 . Application is hosted on port80 and services are listening on port 80 at destination server . When client requests accessing webserver on port 80 client will generate a souce port as per your example it is port 5000 and destination port is port 80 and port ...


15

No, a TCP connection is uniquely identified by both source and destination IP and TCP (port) addresses. Changing any one of those will break the TCP connection (or prevent it from forming in the handshake). What you may be referring to is the fact that a web browser will form, use, and close multiple TCP connections with the web server. Each connection will ...


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