Section 9: IP Addressing Flashcards
(37 cards)
What is an IPv4 address and how many bits does it have?
An IPv4 address is a logical address used to identify a device on a network. It is a 32-bit number.
What are the two main portions of an IPv4 address, and what component defines them?
The Network portion and the Host portion. They are defined by the subnet mask.
What is dotted-decimal notation?
The human-readable format for an IPv4 address, which consists of four decimal numbers (each called an octet), separated by dots.
For example, 192.168.1.4.
What four components are typically required for a full IPv4 client configuration?
- IP Address 2. Subnet Mask 3. Default Gateway 4. DNS Server
What is the primary function of a subnet mask?
To divide an IPv4 address into its network and host portions.
In the binary representation of a subnet mask, what do the 1s and 0s represent?
The 1s represent the network portion of the address, and the 0s represent the host portion.
How does a device use a subnet mask to determine if a destination IP is local or remote?
It checks if the destination’s network address is the same as its own. If it is, the destination is local. If not, the destination is remote, and traffic is sent to the default gateway.
What is the key difference between a public and a private IPv4 address?
A public IP address is globally unique and routable on the internet. A private IP address is for internal network use only and is not routable on the internet.
What are the three blocks of IP addresses defined by RFC 1918 for private use?
10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16.
What is the Class A private IP address range?
10.0.0.0 to 10.255.255.255 (10.0.0.0/8)
What is the Class B private IP address range?
172.16.0.0 to 172.31.255.255 (172.16.0.0/12)
What is the Class C private IP address range?
192.168.0.0 to 192.168.255.255 (192.168.0.0/16)
What technology allows devices with private IP addresses to access the internet?
Network Address Translation (NAT).
What does NAT (Network Address Translation) do?
It translates private, non-routable IP addresses into a public, routable IP address, allowing devices on a private network to access the internet.
If a Windows PC fails to get an address from a DHCP server, what address range will it likely assign to itself?
The APIPA range: 169.254.0.0 to 169.254.255.255.
What does an IP address in the 169.254.0.0/16 range indicate?
It is an Automatic Private IP Addressing (APIPA) address, which means the device was unable to contact a DHCP server.
What is the purpose of the 127.0.0.1 address?
It is the loopback address (or localhost), used to test the TCP/IP protocol stack on the local device without sending traffic onto the network.
What IP address is commonly known as ‘localhost’?
127.0.0.1
What are the four steps of the DHCP process, known by the acronym DORA?
Discover, Offer, Request, Acknowledge.
What is a DHCP scope?
A defined range of IP addresses that a DHCP server is configured to lease to clients on a network.
What feature must be configured on a router to allow DHCP requests to cross subnets?
A DHCP Relay Agent (in Cisco, this is the ip helper-address command).
Why must you subtract 2 when calculating the number of usable host addresses in a subnet?
Because the first address is the reserved Network ID, and the last address is the reserved Broadcast ID.
What are the two primary benefits of subnetting a large network?
- Improved Performance (by reducing broadcast domains). 2. Enhanced Security (by segmenting network traffic).
If you start with a /24 network and borrow 3 bits for subnetting, what is the new CIDR notation for the subnets?
/27 (because 24 + 3 = 27).
