Networks - IP Domain DNS MAC Flashcards
How does IPv4 work?
Each device has a unique 32 bit binary number address.
0101 1001 1001 0001 0100 1101 0110 0110
This sequence is broken into 8-digit chunks called octets. Each octet is changed into denary, separated by dots.
89.145.77.102
What does an IP address contain?
The address of the network.
- Uniquely identify networks
- Send messages between different networks
The address of the node within the network
- Send messages to specific computers within a network
What does IP classes solve?
Not enough room for either node address or network address within the 32 bits given.
What is IP Class A for?
Very large networks
- 16 million nodes
What is IP Class B for?
Medium sized networks
- 64,000 nodes
What is IP Class C for?
Small networks
- 256 nodes
What is a static IP address?
An IP address that doesn’t change.
What is a dynamic IP address for?
Temporary use while a device is connected. As soon as the device disconnects, that IP becomes available for other devices to use.
How many addresses is IPv4 capable of?
4 billion
Why was IPv6 introduced?
There are more internet capable devices online than there are available IPv4 addresses.
How many bits does IPv6 have?
128 bits
Why hasn’t the introduction of IPv6 made any difference to the way the internet runs?
Both IPv6 and IPv4 can coexist.
Why was Domain Name System developed?
IP addresses are not convenient to remember.
What is DNS?
A system that assigns names to IP addresses that use the full set of alphanumeric characters.
How are domains organised and allocated?
By IANA and its member registrars (just like IP numbers)
What are the two parts of a domain?
A descriptive string of characters
EG: brainscape
A suffix describing which Top Level Domain it belongs to
EG: .com
How are domain names registered and handled?
By the Domain Name System
When you enter a URL, how is the IP address of that website retrieved?
An online DNS server receives the domain name request from the browser, and finds the related IP address in a database. It returns that info back.
Why must the DNS be extremely robust and trustworthy?
It has to serve millions of browser requests all of the time.
How does the DNS achieve being extremely robust and trustworthy?
There is a network of hundreds of DNS root servers around the world.
What do the root DNS servers contain?
Is there anything they do?
Backups of the entire IP database. Some have the authority to hand out domains for specific TLDs
How do the root DNS servers stay up to date?
They check with each other.
Why must root DNS servers keep up to date?
Domain names are being bought and sold constantly.
What happens if someone enters a domain name into their browser that the DNS doesn’t recognise?
An error code is sent back to the web browser.
“Website cannot be found” displayed.
What is a MAC address useful for? Why?
MAC is useful for network diagnostics because it never changes, so it can identify individual devices.
How is a MAC address formatted and displayed as?
A set of six hexadecimal numbers separated by hyphens.
How does MAC filtering work?
Networks can be configured to only accept connections from devices with a MAC address from an approved list.
What benefit does MAC filtering have?
It prevents unknown devices from getting into the network.
