TCP Headers Flashcards
Source Port
Identifies the port where the TCP connection is open on the node sending the message.
Destination Port
Identifies the port where the TCP connection is open on the node receiving the message.
Sequence Number
Used to keep track of the order of data transmitted in a TCP connection. It changes over time as more data is transmitted by increasing the value based on the number of bytes of data transmitted in each segment.
Acknowledgement Number
Used to keep track of the data that has been successfully received by indicating the next byte of data the node is expecting to receive.
Header Length/Data Offset
Specifies the size of the TCP header in 32-bit words. This means that the size of the TCP header can be found by multiplying the Data Offset value by 4.
Used to indicate a particular state of connection or to provide some additional useful information.
Flags
TCP flag: if set, โ๐ถ๐ณ๐จ๐ฆ๐ฏ๐ตโ pointer is valid
URG
TCP flag: If set, ๐๐๐ ๐ฏ๐ถ๐ฎ๐ฃ๐ฆ๐ณ is valid
ACK
TCP flag: if set, immediately pass data to application
PSH
TCP flag: Used to facilitate connection setup
SYN
TCP flag: Used for connection termination
FIN
Window Size
Specifies the maximum amount of data the receiver can receive and store in memory without overflowing its buffer, which can result in data loss and transmission errors.
Checksum
Holds a value calculated from the data in a message, that is used to detect errors that may have occurred during transmission.
Urgent Pointer
It was meant to be used to send data in a TCP packet straight to the application. Not recommended for use.
Options: Max segment size the sender will accept
Maximum Segment Size
