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
Whilst these firewalls use much fewer resources than alternatives, they are much dumber. For example, these firewalls are only effective as the rules that are defined within them. If a rule is not exactly matched, it is effectively useless.
Stateless
What layers of the OSI model do firewalls operate at?
Layer 3 and Layer 7
What does VLAN stand for ?
Virtual Local Area Network
What does VLAN stand for ?
Virtual Local Area Network
What does DNS stand for ?
Domain Name System
What does TLD stand for in relation to a Domain Name System ?
Top Level Domain
What part of a Domain Name is the Top Level Domain ?
The righthand part of the domain name, i.e. .com or .co.uk etc
What are the two types of Top Level Domain ?
gTLD (Generic Top Level) and ccTLD (Country Code Top Level Domain).
Examples of Generic Top Level Domains
.com
.gov
.edu
.org
Examples of Country Code Top Level Domains
.ca
.co.uk
.au
What is the Second Level Domain ?
The main body of the domain name. for example in www.google.com “google” is the Second Level Domain
How many characters is a Second Level Domain name limited to ?
64 characters
Where would you find a Subdomain ?
On the left hand side of the Second Level Domain using a period to separate them e.g. admin.tryhackme.com. Admin is the Subdomain.
What is the max length of a Domain Name
253 characters
An A Record DNS record resolve to what type of address ?
An IPv4 address
An AAAA Record DNS record resolve to what type of address ?
IPv6 address
What does a CNAME DNS record resolve to ?
Another domain name
What does an MX DNS Record resolve to ?
These records resolve to the address of the servers that handle the email for the domain you are querying
