12.1.6 IPv4 Addressing Facts

What does DHCP do?

It automatically assigns IPv4 addresses and other TCP/IPv4 configuration settings to hosts.

When should DHCP be used?

For small, medium, or large networks needing automatic host configuration.

What additional settings can DHCP provide besides an IP address?

Default gateway, DNS servers, and other TCP/IPv4 configuration parameters.

What is the default IPv4 configuration method for Windows computers?

DHCP

What does APIPA stand for?

Automatic Private IPv4 Addressing

When do Windows computers use APIPA?

When a DHCP server cannot be contacted.

What IP address range does APIPA use?

169.254.0.1 to 169.254.255.255

What subnet mask does APIPA use?

255.255.0.0

What does a host do before using an APIPA address?

It checks to make sure no other host is using that address.

Why can't APIPA be used across multiple subnets?

Because it does not assign a default gateway.

When is APIPA most useful?

On small single-subnet networks without internet or DNS needs.

What is static IPv4 assignment?

Manually entering the IP address and related network settings for a host.

What must be configured with a static IP address?

Subnet mask and default gateway

What happens to DHCP and APIPA when a static IP is configured?

They are disabled.

When is static addressing recommended?

For servers, small stable networks, and devices needing the same address every time.

Why must duplicate static IP addresses be avoided?

Because duplicate addresses cause network communication problems.

What is alternate IPv4 configuration?

A backup static configuration used if DHCP fails.

How does alternate IPv4 configuration work?

The host tries DHCP first, and if DHCP fails, it uses the alternate settings.

When is alternate IPv4 configuration useful?

For laptops or devices connecting to networks with and without DHCP.

What happens to APIPA when alternate IPv4 configuration is set?

APIPA is never used.

What does a NAT router do?

It translates multiple private IP addresses into one public registered IP address.

Why is NAT used?

To allow multiple private devices to share one public internet IP address.

What type of network is the internet considered?

A public network

What must all devices on a public network have?

A unique registered public IP address.

Who assigns public IP addresses?

The ISP

What type of network uses private IP addresses internally?

A private network

How does a NAT router keep track of multiple devices?

It associates a port number with each private IP address.

Who controls and issues public addressing?

IANA (Internet Assigned Number Authority)

What is the private IP range for Class A private addresses?

10.0.0.0 to 10.255.255.255

What is the private IP range for Class B private addresses?

172.16.0.0 to 172.31.255.255

What is the private IP range for Class C private addresses?

192.168.0.0 to 192.168.255.255

Why are private IP addresses not routed on the internet?

Internet routers are configured by default not to route private addresses.