Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

C&IT > IP Addresses > Flashcards

IP Addresses Flashcards

1
Q

What is an IP address?

A

Internet protocol address. Unique number used to address/identify a host computer or node which communicates over IP on the internet.

Currently IPv4 and IPv6.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

How big is an IPv4 in bits?

A

32 bits/4 bytes.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How many possible addresses in IPv4?

A

Around 4 billion.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the reserved addresses?

A
  1. x.y.z is reserved for loopback, in which a host’s IP software treats an outgoing packet as incoming
  2. x.y.z, 172.16.0.1 to 172.31.255.255 and 192.168.y.z are private, non-routable addresses used for LANs or private WANs only.
    x. x.x.0 - reserved as network identifier.

x.x.x.255 - reserved as a broadcast address on a subnet.
The last address in a network (e.g. x.y.z.255) is reserved as the broadcast address on that network for sending data simultaneously to all hosts on that network.

x.x.x.1: Typically used as default address of a router.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the two parts of an IPv4 address?

A

Network identifier (or network ID) – Left-hand bits of the 32-bit number, used to define the network where nodes are communicating.

Host identifier (or host ID) – Right-hand bits of the 32-bit number, used to identify separate nodes on the network.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Difference between routable and non-routable IPs?

A

Routable - public.
These IPs are assigned to devices connected directly to the public or global internet and are unique.

Non-routable are private.
Assigned internally to devices on a private network.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Why was IPv6 introduced?

A

IPv4 has 4 billion combinations - which was enough when introduced.

But now we need more. We hit 8.7 billion devices on the internet in 2012, but use tricks/workarounds to not have to completely switch over to IPv6.

2018 we’re up to 34.8 billion devices.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How many bits in IPv6?

A

128 bits/16 bites.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How many combinations does IPv6 have?

A

340 trillion, trillion, trillion combinations.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is DHCP system?

A

Dynamic host configuration protocol.

A DHCP server is a device which is responsible for automatically assigning a dynamic IP address from a pool of available addresses to a computer which needs to operate on a public network or on a private network.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Benefits of DHCP?

A

Helps with the issue around the shortage of IPv4 addresses. Active computers request addresses and release them again back to the pool.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How does DHCP work?

A

For example with a phone,

Phone sends out a DHCP discovery message, effectively saying it needs an IP address.
All-in-one Router/Modem/WAP running DHCP sends an offer message with an IP available and a lease time - how long it’s available for.
Phone sends DHCP request message requesting the IP.
Router sends DHCP ACK message and assigns IP to phone.

Uses broadcast IP when waiting for IP.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

When did IPv4 and IPv6 come into use?

A

1984 and 1996.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Examples of private IPs?

A
  1. 0.0.1 - 10.255.255.255
  2. 16.0.1 - 172.31.255.255
  3. 168.0.1 - 192.168.255.255

These addresses are non-routable across the internet and are reserved for use within LANs or private WANs.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How did we fix the issue of private IPs being able to communicate with each other?

A

Network Address Translation (NAT)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Downside to class based networks?

A

Because the range is private, they can subdivide this vast space to suit their network design.

All devices have access to other devices in the network because they are all part of the same network. Another mobile phone provider can use the same range of addresses and this can be endlessly replicated across other large organisations.

However, any device in one organisation could not directly communicate with a device on another organisation’s network. This initially was not considered a real issue because much of the traffic between devices was within an organisation’s network.

Those devices which needed to communicate outside an organisation, such as web servers and mail servers, were still allocated addresses from the public (routable) address range.

However, it soon became apparent that while much of the traffic was intra-organisational, increasingly users needed to access resources that were on the public internet, thanks to mobile phones!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What class do mobile phone providers tend to use?

A

Your mobile phone provider (which has a huge network) most likely allocates addresses from the old Class A range.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What classes do most small offices/schools use still?

A

Schools, colleges, and other medium size organisations often allocate addresses in the old Class B range.

19
Q

Why do most home ips start with 192.168?

A

Most private networks still use (outdated) class conventions.

At home (a small network) your devices are likely to have IP addresses in the format 
192.168.x.x in the Class C range.
20
Q

What was the class system?

A

Historically, the three ranges of private addresses were designated for different size networks. These were referred to as Class A, B, and C networks.

These class based networks would also have fixed size subnet masks.

Class A networks had an 8-bit network id and a 24-bit host id (i.e. could have up to 16,777,214 hosts).
Class B networks had an 16-bit network id and a 16-bit host id (up to 65,534 hosts).
Class C networks had a 24-bit network id and an 8-bit host id (up to 254 hosts).

21
Q

Benefits of a classless system?

A

103.27.104.92/24

This indicates that the first 24 bits of the IP address are the network ID. Using this classless system allows the split between network and host to be anywhere, thus giving more flexibility.

22
Q

What is subnetting?

A

Subnetting is a way of splitting a network up into smaller mini networks without wasting IP addresses.

Standard home routers can support up to 250 devices and you can use subnetting to seperate parts of the network from each other whilst still allowing all devices to access the internet.

Conventionally the router is given the first or last address in the range. So, if the host id is 8 bits, the router would be allocated the id 1 or 254 (remember that 0 and 255 are reserved and cannot be used).

.

23
Q

How does NAT work?

A

With NAT, a pool of public IP addresses is held by an edge router (at the point where it connects to the internet).

Any packet heading out to the internet, with a private IP address as its source address, has swapped the private address for a public, routable address. This is then routable over the internet and the response comes back to the right place. A single routable IP address can be used for an entire private network.

NAT can also provide port forwarding.

24
Q

What is NAT?

A

Network Address Translation

Devices using private IP addresses cannot access the internet directly as they are not routable and cannot be used for routing packets on the internet. They are also not unique, making them unable to receive packets back.

Instead, they must communicate via another network device that provides network address translation (NAT).

25
Q

What is port forwarding?

A

Port forwarding allows remote computers (i.e. computers on the internet) to connect to a specific computer, or service within a private local area network.

26
Q

Who would use subnetting?

A

A large organisation may wish to create subnet segments to ease management and improve efficiency by routing data through one segment only. A bus network could be created, allowing the computers in Subnetwork A to communicate at the same time as computers in Subnetwork B without any collision. It also reduces the size of the broadcast domain, improving security, speed and reliability.

27
Q

Pros of subnetting?

A

Increases security and network performance.

Subnet masks break up networks into smaller mini sub-networks without wasting IP addresses.

Breaking a large network up into smaller network reduces the network traffic because network broadcasts only go out other parts of the subnet, not the whole network. Without this a large network would be susceptible to a broadcast storm, where large amounts of broadcasts can seriously impede the performance of a network.
Having subnets of a larger network is more secure and also easier to troubleshoot as only part of a network would be affected by network issues.

28
Q

What is a subnet mask?

A

A way of identifying the NetID and HostID portions of an address. Your computer masks it’s own IP and then checks the recipient IP to see if it’s the same using AND operator.

Can also split networks up into smaller equal sized sub-networks.

29
Q

Why do we need to know which part is which is an IP address?

A

When sending data from one IP address to another there’s 3 possibilities:

1) The IP is on the same network and the data is sent directly to the recipient via the switch/other network hardware.
2_ The IP is on a diff network and the data is sent to the gateway and onto another network.
3. Address doesn’t exist.

30
Q

How to work out broadcast and NetID from IP sub mask?

A

Start off with IP and replace all host bits with 0s. Broadcast replaces host with 1s.

31
Q

Why do we need a broadcast/what is it?

A

The last value of an IP address. As soon as a computer connects to a network it doesn’t have an IP, but it needs to get one but it needs to listen in order to recieve the IP address it can use from DHCP so it listens on the last address - the final address available.

32
Q

What is CSMA?

A

CSMA stands for carrier sense multiple access, which means that every node on the network must monitor the bus for a period of no activity before trying to send a message on that bus (carrier sense).

Once this period of no activity occurs, every node on the bus has an equal opportunity to transmit a message (multiple access). The CD stands for collision detection.

33
Q

What does multiple access mean in terms of CSMA?

A

Once a period of no activity occurs, every node on the bus has an equal opportunity to transmit a message (multiple access)

34
Q

What is the network identifier/subnet IP?

A

x.y.z.0.

35
Q

How do we ensure hosts and routes are uniquely identified on a world wide scale?

A

They’re assigned by global organisations such as IANA.

36
Q

What is a routing table?

A

A set of rules used to determine where data packets traveling over an Internet Protocol (IP) network will be directed.

Routing tables in routers contain world wide unique address info so they can send on packets.

37
Q

What happens if a private IP sends data packets to a public/global internet router?

A

Public/global internet routers will reject any data packets with source or destination IP addresses which are in the private ranges.

38
Q

Why do we say private IP addresses are non routable?

A

Routers will not forward them on.

39
Q

Benefit of computers having private IPs?

A

Reduces the need for every computer to have its own unique public address.

40
Q

What’s a loopback address?

A

127.x.y.z is reserved for loopback, also called localhost.

Loopback is a method your computer/virtual network uses to connect with itself and communicate.

For example, if a host device successfully hits up 127.0.0.2 or any IP address from the above-mentioned loopback range, then all is good. This would imply that the IP/TCP stack on the device is successfully loaded and working.

41
Q

What is CIDR?

A

Classless inter-domain routing. Increases flexibility of IPv4 system. A suffix is used such as 192.30.250.00/18 which means 18 bits will be used for the net ID and the last 14 bits will be used for the host.

42
Q

Benefits of IPv6 over IPv4?

A

No need for NATS
Removes riusk of private IP collisions
Built in authentication
Allows for more efficient routing.

43
Q

What is zero routing?

A

A way to shorten IPv6 addresses. Can be applied once to move 0000:0000 section.

900B:3E4A:AE41:0000:0000:AFF7:DD44:F1FF

Becomes:
900B:3E4A:AE41::AFF7:DD44:F1FF

44
Q

What are public IP addresses used by?

A

DNS servers, network routes, directly controlled computers.

C&IT (2 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions