Midterm Flashcards
(41 cards)
What does the firewall do?
Filters packet-by-packet based on source, destination, IP addresses, and port numbers. TCP SYN and ACK bits. ICMP message type. DPI.
What is the OSI model?
The OSI model defines 7 layers for how networked systems should communicate. Layers can be swapped out without affecting other layers
Name the Layers of the OSI model.
- Physical
- DataLink
- Network
- Transport
- Session
- Presentation
- Applications
Give an example of a device/protocol at layers 1, 2, 3, 4
- Wiring
- Ethernet
- IP
- TCP
What does a VPN do?
A VPN is a way to access a private network on the public internet in a private way.
What’s the purpose of NAT?
The basic purpose of NAT is to multiplex traffic from the internal network and present it to the Internet as if it was coming from a single computer having only one IP address.
When it comes to cat5e and fiber, what are the advantages/disadvantages of copper and fiber?
Copper is cheap and easy to make connections for. Fiber can go much longer distances, and it is faster.
What are the common wireless frequencies?
2.4Ghz and 5Ghz
Which protocols are reliable?
Most are not reliable. IP and UDP are not reliable. The only reliable protocol is TCP because it is going to guarantee that your data with will get to it’s destination.
What is the TCP 3 way handshake?
Host A sends an SYN (open) to host B
Host B returns an SYN acknowledgement (SYN ACK)
Host A sends an ACK to acknowledge the SYN ACK
What is the difference between a switch/hub/router?
A Hub is at the Physical Layer (Layer 1) and joins multiple input lines electrically. A Switch is at the Data Link Layer (Layer 2) and it is a device that filters and forwards packets between LAN segments. A Router is a device that forwards data packets along networks, and are located at gateways, the places where two or more networks connect.
What does CSMA/CD do?
It is a set of rules determining how network devices respond when two devices attempt to use a data channel simultaneously (called a collision)
What does ARP do?
ARP turns IP addresses into MAC addresses.
What does DHCP do?
DHCP assigns a dynamic IP address to devices. It assigns a different/unique IP address to a device when it connects to the network.
Give an example of a Link State Protocol
ISIS and OSPF
Give an example of a Distance Vector
RIP and IEGRP
What is the benefit of encapsulation?
Encapsulation is important to keeping each layer simple, logically separate, but inter-operable with other layers. Also it allows the ability to modify one layer without affecting the other layers.
What is the difference between an IP address and a MAC address?
(might be something different but…)
Your IP address is your address to the world on the internet. Every connection to the internet gets a unique IP address. But with a MAC address, every network DEVICE get’s a unique address, regardless if it’s on the internet or not. Your hardware manufacturer builds it into your device.
What is the purpose or RIR’s?
Distribute IP addresses around the world. Allocates to large ISPs and large institutions.
What port is SSH?
Port 22
What port is SMTP?
Port 25
What port is DNS?
Port 53
What port is HTTP?
Port 80
What port is FTP?
Port 21
