1.3 Protocols And Packet Analysis Flashcards
An agreement between Network entities, such as hosts and servers, for how they will communicate.
Network protocol
Where each protocol layer receives a service from the layer below it and provides a service to the layer above it.
Protocol stack
Protocol stack that divides network communications into seven layers.
OSI model
Acronym for the seven layers of the OSI protocol stack
All people seem to need data processing.
People Don’t Need Those Stupid Packets Anyways.
Physical, data link, network, transport, session, presentation, application.
Blocks of data that describe work that was done at a corresponding layer.
Headers
An attacker forges the IP address in the IP header to make a communication appear to originate from an IP address that it isn’t.
IP address spoofing
the process of moving down a protocol stack with each layer doing work and leveraging the addition of a header to describe said work
Encapsulation
the process of moving up a protocol stack with each layer doing work combined with the reading and removing of headers.
Decapsulation
Whenever we discuss network communications and the corresponding layers we must always reference this model
OSI model
Mnemonic for the TCP/IP model
Never Interrupt The Aardvark
Network, internet, transport, application.
The core routing protocol of the internet. Handles the transmission of packets between Network endpoints. It’s job is to determine the best route for a communication between two endpoints on two different networks.
IP - internet protocol
Allows for IPv6 communication between two IPv6 endpoints over IPv4 without the routing systems requiring any knowledge of ipv6.
IPv6 over IPv4 (tunneling)
Allows ipv4 addresses to be translated from their current form into IPv6 compatible addresses.
Ipv4 over IPv6 translation
This layer of the OSI model is responsible for determining the routes to be taken between two network devices.
Network layer, layer three
Protocol whose primary purpose is to report error conditions.
ICMP - internet control message protocol
A session oriented communication protocol, operating at the transport layer of the OSI model.
TCP - transmission control protocol
Layer 3 protocol that establishes a session between hosts prior to data exchange.
TCP - transmission control protocol
A use of TCP that allows for the communicating hosts to exchange messages to affect how much data can be transmitted at any given time.
Flow control
Layer 3 OSI protocol that can allow you to map a computer, to know that it is alive and a port is available.
ICMP - internet control message protocol
TCP flag that is used to indicate that the computing systems are synchronizing their sequence numbers.
SYN - synchronize
TCP flag that is used to acknowledge the next sequence number a computer expects to receive.
ACK - acknowledge
TCP flag that is an integer that will assist in the tracking of data that is being communicated in either direction.
ISN - initial sequence number
These numbers indicate where applications on a computer system are expecting to send and receive their network communications.
Port numbers
Port numbers in the range of 1024 to 65535 for client use.
Ephemeral port numbers
Port numbers in the range of 1 to 1023 for the use of servers.
Privileged port numbers
