IPv4 Addressing and RFC 1918

18 Questions

What is the primary reason for not running out of IPv4 addresses despite the large number of users on the internet?

Private IP addresses are used inside corporate networks

What is the purpose of RFC 1918?

To standardize private IP addresses for organizations

What is the benefit of using private IP addresses inside corporate networks?

To conserve public IPv4 addresses

What type of addresses can be used without reporting to the internet authorities?

Private IPv4 addresses from RFC 1918

What is the scope of RFC 1918 in terms of IP address allocation?

For class A, B, and C networks

What is the result of using private IP addresses from RFC 1918?

Reduced need for public IP addresses

What type of entity can use private IP addresses from RFC 1918?

Any entity autonomously operating an IP network

What is the specific range of IP addresses that can be used without reporting to authorities?

10.0.0.0 - 10.255.255.255

What is the primary reason companies use RFC 1918 private address space?

To avoid having to report IP addresses to an official reporting service

What is the purpose of DHCP in a corporate network?

To identify IP addresses or ranges of IP addresses to hand out

What is the challenge of using RFC 1918 addresses in a corporate network?

They are not routable over the public internet

What is the solution to the problem of RFC 1918 addresses not being routable over the public internet?

Implementing Network Address Translation (NAT)

What type of IP addresses are used on the internet?

Class A, Class B, and Class C addresses

What is the purpose of a default gateway in a corporate network?

To forward packets off of the local network

What is the primary advantage of using RFC 1918 private address space?

It allows companies to avoid reporting IP addresses to an official reporting service

What is the relationship between NAT and PAT?

PAT is a type of NAT

Why do companies likely use DHCP in their corporate networks?

To identify beforehand what IP addresses or ranges of IP addresses to hand out

What is the primary difference between private RFC 1918 addresses and routable IPv4 addresses?

Private addresses are not routable over the public internet

Study Notes

IPv4 Address Challenges

IPv4 addresses are not infinite, and there's a shortage due to millions of internet users.
One solution is to use private IP addresses inside corporate networks, as described in RFC 1918.

RFC 1918 Private IP Addresses

RFC 1918 is a standard for private IP addresses used inside organizations.
It sets aside specific IP address ranges for corporations to use without needing to report or assign.
These private addresses can be used without coordination with the internet.

Private IP Address Ranges

Class A range: 10.0.0.0 to 10.255.255.255
Class B range: 172.16.0.0 to 172.31.255.255
Class C range: 192.168.0.0 to 192.168.255.255

Using Private IP Addresses

Companies use DHCP to assign private IP addresses to devices.
Devices receive an IP address, subnet mask, DNS server, and default gateway.
Most corporations use private IP addresses because they don't need to report to an official service.

The Internet Challenge

Private IP addresses are not routed on the public internet.
If a device with a private IP address wants to access the internet, it needs to be translated into a routable IP address.

Solution: Network Address Translation (NAT)

NAT translates private IP addresses into routable IP addresses for internet communication.

This process is achieved through the use of a Layer 3 router, which examines the source and destination IP addresses of outgoing and incoming data packets, respectively. By substituting the private IP addresses with the public IP address of the router, NAT enables multiple devices on the private network to share the same public IP address.
This allows devices on a private network to access the internet using a shared public IP address.

This is particularly useful in large-scale networks, where the number of public IP addresses may be limited. By implementing NAT, network administrators can conserve IP address space and simplify network management.

Learn how IPv4 addresses are managed to prevent depletion and the role of RFC 1918 in corporate networks.

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