Chapter 4

• FTP (Data) - 20 TCP
• FTP (CONTROL) - 21 TCP
• SSH (Secure Shell Protocol) - 22 TCP
• TelNet - 23 TCP
• SMTP - 25 TCP
• DNS - 53 UDP
• DHCP (Server Port) - 67 UDP
• DHCP ( Client Port) - 68 UDP
• TFTP - 69 UDP
• HTTP - 80 TCP
• POP3 - 110 TCP
• HTTPS - 443 TCP
• Well-known ports

  0 - 1023
• Registered ports

  1024 - 49151
• Dynamic/Private ports

  49152 - 65535
• OSI Transport Layer Purpose

  identifying the different applications, tracking individual communications, data segmentation, segment reassemble, flow control, error checking and recovery
• Protocols involve in Layer 4

  Transmission Control Protocol and User Datagram Protocol
• Ports are assigned by

  Internet Assigned Numbers Authority
• TCP Header fields


  Source port, destination port, sequence number, acknowledgement number, data offset, reserved, flag, window size, checksum, urgent, option, application layer data
• port numbers identify which _ of application layer is in use

  service
• Sender side: Segmentation, Receiver side: _

  Reassemble
• flow control which enables the receiver to not be overwhelm is perform only by _

  tcp
• flow control is done using what field in tcp header?

  window size
• Error checking

  tcp and udp
• recovery

  tcp
• which field indicate if specific data is received of not

  acknowledgement number
• use to ensure reliability

  sequence number and acknowledgement number
• size of the tcp header is in what field

  data offset
• types of flags

  synchronize, acknowledgement, finish, reset, push, urgent
• if the data send is not correct, receiver side will_

  drop it
• header length + application data

  window size
• a mechanism to check integrity of data

  checksum
• udp header fields

  source port, destination port, length, checksum
• pertains to the information in the headers

  overhead
• randomly generated ports

  dynamic or private ports