Ch 8 Networking Fundamentals Flashcards
What is the main purpose of a router?
to connect networks to one another
What kind of network requires an IP that is globally unique?
The Internet!
How many unique IP addresses can IPv4 create?
4 billion
Private networks solve what problem?
There aren’t enough unique IPv4 addresses for all the devices that exist, and IPv6 is annoying
What IP addresses have been reserved for private, internal networks?
10.0.0.0/8 (a single Class A network)
172.16.0.0/12 (16 Class B networks)
192.168.0.0/16 (256 Class C networks)
Can a private network IP reach the internet?
not directly (and vice versa… nodes from other networks cannot easily reach them)
What is NAT used for?
Makes it easier for a private IP device/internal network device to reach the internet or an outside network
What does NAT mean?
Network Address Translation
How does NAT work?
When a private IP device tries to reach the internet, a NAT router replaces that IP with its own public facing IP.
outside nodes think they are communicating directly with host when they’re directly communicating with the NAT router.
The NAT router uses tables to keep track of all cnxns that currently exist for the hosts in the network.
NAT is common and embedded in most routers (homes and small businesses)
What could a long string of zeros in an IPv6 address be replaced with?
:: colons
What is a subnet mask?
tells you what numbers in an IP indicate the network and which indicate the node within the network
CIDR stands for
classless inter-domain routing
Give an example of CIDR notation for an IP
192.168.10.100/24
What does the 24 in 192.168.10.100/24 stand for?
a 24 bit network address is used.
What is the classical notation version of the CIDR notation version 192.168.10.100/24?
192.168.10.100/255.255.255.0
the 255.255.255.0 is the 24. 24 bits out of 32 bits are turned on for the network.
How many bytes in an IP address?
4 (8 bits is a byte)
How are bytes typically allocated in an IP address?
first three bytes are for network and last byte is for hosts
For an IP address of 192.168.10.100/24, what would the network address be?
In this case, since the first three octects (bytes) is the subnet mask (24 = 8*3 = 3 octets), then the network IP is 192.168.10.0
What is the broadcast address?
This is an address that can address all the nodes in a network
How can you find the broadcast address?
Take all the host bits and turn them to 1.
192.168.10.100/24 with this IP example, that last octect (32-24 = 8 bits or one byte or one octet) – we have 8 host bits. turn them all to 1 and we get 255
So broadcast address for 192.168.10.100/24 or the 192.168.10.0 network is 192.168.10.255
What is variable length subnetting?
When a subnetting mask does not fit a neat octet
only a part of the byte is used for addressing nodes, and the rest is used for the network
What’s an example of variable length subnetting?
212.209.113.33/27
you only have the last 5 bits of the last byte for addressing hosts (2^5 = 32 hosts) and the first three for addressing the network (2^7 + 2^6 + 2^5 + 0 + 0 + 0 + 0 + 0 )
What would 212.209.113.33/27 be in binary notation?
11010100.11010001.00001010.00100001
is the host
/27 = 11111111.11111111.11111111.11100000
If an IP in binary notation is 11010100.11010001.00001010.00100001, and the network mask in binary notation is /27 = 11111111.11111111.11111111.11100000, then what is the subnet IP?
since the last octect of the mask is 11100000(224), and the last octect of the IP is 00100001(33), then the subnet IP is the first three of the IP === 00100000 (32)
so 212.209.113.33/27 belongs to network 212.209.113.32/27
broadcast address (where all host bits are set to 1s) is 212.209.113.63
63-32 = 32 addresses. one is for network address (gateway) and one for the broadcast. so the rest, 30, are for host addresses
Every NIC has a …
MAC address
How many bytes is a mac address?
12
What kind of addressing is used within networks but can’t be used to talk to other networks?
MAC addresses
What kind of address must be paired with an IP address?
a MAC address
How do MAC addresses help with finding a node?
They find the NIC that goes with an IP
What are the first 6 and then the last 6 of a MAC address?
first six: vendor ID
last six: unique node ID
What part of the MAC ID needs to be registered?
The first six bytes that are the vendor ID
How do you identify the services on a server?
through its ports and protocols
What is 00100000?
32
What is 01000000
64
What is 01100000
96
What is 10000000
128
What is 10100000
160
What is 11000000
192
What is 11100000
224
