tryhackme notes Flashcards
What type of DHCP packet is used by a device to retrieve an IP address?
DHCP Discover
What type of DHCP packet does a device send once it has been offered an IP address by the DHCP server?
DHCP Request
What is the last DHCP packet that is sent to a device from a DHCP server?
DHCP ACK
What type of DHCP packet does the server reply back with an IP address the device could use ?
DHCP Offerr
What does TCP stand for?
Transmission Control Protcol
What does UDP stand for?
User Datagram Protocol
What does OSPF stand for ?
Open Shortest Path First
What does RIP stand for ?
Routing Information Protocol
On what layer would you find the Open Shorted Path First Protocol ?
Network Layer
On what layer would you find the Routing Information Protocol ?
Network
This field sets an expiry timer for the packet to not clog up your network if it never manages to reach a host or escape!
Time to Live
This field provides integrity checking for protocols such as TCP/IP. If any data is changed, this value will be different from what was expected and therefore corrupt.
A Checksum
This value is the port opened by the sender to send the TCP packet from. This value is chosen randomly (out of the ports from 0-65535 that aren’t already in use at the time).
Source Port
This value is the port opened by the sender to send the TCP packet from. This value is chosen randomly (out of the ports from 0-65535 that aren’t already in use at the time).
Destination port
When a connection occurs, the first piece of data transmitted is given a random number. We’ll explain this more in-depth further on.
Sequence Number
After a piece of data has been given a sequence number, the number for the next piece of data will have the sequence number + 1. We’ll also explain this more in-depth further on.
Acknowledgement Number
This header determines how the packet should be handled by either device during the handshake process. Specific flags will determine specific behaviours, which is what we’ll come on to explain below.
Flag
What packet is sent to close a connection ?
A FIN Packet
The term given for the process used to establish a connection between two devices.
A Three Way Handshake
Provide the order of a normal Three-way handshake
Syn, Syn/Ack, Ack
What type of connection is UDP ?
Stateless
This type of firewall uses the entire information from a connection; rather than inspecting an individual packet, this firewall determines the behaviour of a device based upon the entire connection.
Stateful
This firewall type consumes many resources in comparison to stateless firewalls as the decision making is dynamic. For example, a firewall could allow the first parts of a TCP handshake that would later fail.
Stateful
This firewall type uses a static set of rules to determine whether or not individual packets are acceptable or not. For example, a device sending a bad packet will not necessarily mean that the entire device is then blocked.
Stateless
