Week 6 Flashcards
Error-detection
The ability for a protocol or program to determine that something went wrong
Error-recovery
The ability for a protocol or program to attempt to fix it
ICMP
Is used by the router to communicate that data wasn’t sent back to the source of the data
Internet Control Message Protocol
Ping
Lets you send a special type of ICMP message called an Echo Request
How do you send a ping?
Enter into the command line “ping” followed by the destination IP address
Traceroute
A utility that lets you discover the path between two nodes, and gives you information about each hop along the way
What are two similar tools to traceroute?
mtr-Linux/MacOS
pathping-Windows
mtr
Works in real time and will continually update its output with all the current aggregate data about the traceroute
pathping
Runs for 50 seconds and then displays the final aggregate data all at once
What are two tools to test transport layer?
netcat-Linux/MacOS
Test-NetConnection - Windows
What are the two necessary arguments for nd (netcat)?
Host and Port
nslookup
nslookup [hostname]
stands for name server lookup
Work as a check against the configuration of DNS servers
What kind of server does an ISP give the user access to as part of the service?
Recursive name server
Public DNS servers
Name servers specifically set up so that anyone can use them for free
What IPs do Level 3 Communications use for their public DNS servers?
4.2.2.1 - 4.2.2.6
What are the IPs of Google’s public DNS servers?
8.8.8.8 and 8.8.4.4
What is a good use of public DNS servers?
Testing general internet connectivity by sending s ping request to one
Registrar
An organization responsible for assigning individual domain names to other organizations or individuals
Hosts files
A flat file that contains, on each line, a network address followed by the host name it can be referred to as
Loopback address
A way of sending network traffic to yourself
IP is 127.0.0.1
Configured on an entry in a host file
What is a popular way viruses disrupt and redirect user traffic
Host files
What are examined before a DNS resolution attempt occurs on just about every major OS?
Host files
Cloud computing
A technological approach where computing resources are provisioned in a shareable way, so that lots of users get what they need, when they need it
A model in computing where large clusters of machines let us use the total resources available in a better way
Virtualization
A single physical machine called a host country!d run many individual virtual instances, called guests
Hypervisor
A piece of software that runs and manages virtual machines, while also offering these guests a virtual operating platform that’s indistinguishable from actual hardware
Public cloud
A large cluster of machines run by another company
Private cloud
Used by a single large corporation and generally physically hosted on its own premises
Hybrid cloud
Term used to describe situations where companies might run things like their most sensitive proprietary technologies on a private cloud, while entrusting their less sensitive servers to a public cloud
Infrastructure as a Service (IAAS)
You shouldn’t have to worry about building your own network or your own servers
Platform as a Service (PAAS)
A subset of cloud computing where a platform is provided for customers to run their services
Software as a Service (SAAS)
A way of licencing the use of software to others while keeping that software centrally hosted and managed
Cloud storage
Allows data to be held at multiple cloud storage facilities potentially around the globe which allows a company to grow their storage as needed without the headache of adding to their own physical hardware and monitoring the hardware components
What are the two rules for shortening IPv6 addresses?
- You can remove any leading zeros from a group
2. Any number of consecutive groups composed of just zeros can be replaced with two colons
Link-local unicast addresses
Allow for local network segment communications and are configured based upon a host’s MAC address
FE80::
What bits are reserved for the network ID and host ID
First 64 bits for network ID
Second 64 bits for host ID
Traffic class field (IPv6)
An 8 bit field that defines the type of traffic contained within the IP datagram and allows for different classes of traffic to receive different priorities
Flow label field
A 20 bit field that’s used in conjunction with the traffic class field for routers to make decisions about the quality of service level for a specific datagram
Payload length field
16 bit field that defines how long the data payload section of the datagram is
Next header field
Unique to IPv6
Defines what kind of header is immediately after this current one
Hop limit field
8 bit field identical in purpose to the TTL field in an IPv4 header
How to tell if an IPv6 address is correlated with an IPv4 address?
The IPv6 address starts with 80 zeros and is followed by 16 ones. The remaining 32 digits are the IPv4 address meant to be represented
IPv6
Servers take incoming IPv6 traffic and encapsulate it within traditional IPv4 datagram
IPv6 tunnel broker
Companies that provide IPv6 tunnel!ing endpoints for you, so you don’t have to introduce additional equipment to your network
