IPv4

Todo

I studied this page before starting this website, so it’s a stub. I’ll circle back and add info as I can!

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Static Routing

Private IPv4 Addresses

IPv4 simply does not provide enough addresses for all devices that need an IP address in the modern world. While the long-tern solution to this problem is the still-ongoing transition to IPv6, there are several short-term solutions to mitigate the address shortage:

1. CIDR
2. Private IPv4 Addresses
3. Network Address Translation (NAT)

RFC 1918 specifies these address ranges as private:

• 10.0.0.0/8 (10.0.0.0 to 10.255.255.255) ----------⇒ Class A
• 172.16.0.0/12 (172.16.0.0 to 172.31.255.255) ----⇒ Class B
• 192.168.0.0/16 (192.168.0.0 to 192.168.255.255) ⇒ Class C You are free to use addresses in these ranges in your networks as you like. They don’t need to be globally unique. That said, because they aren’t globally unique, they cannot be used over the Internet. ISPs will simply drop any traffic that originates from these addresses.

If these addresses can’t be used to route traffic over the Internet, how can home PCs connect to it? Even if they were allowed to route over the Internet, there would be an enormous number of duplicate addresses — routing traffic to the correct locations would be impossible! The solution is Network Address Translation (NAT)

In a nutshell, Network Address Translation (NAT) allows multiple devices on a local network to ‘borrow’ a single public IP (which is assigned by the ISP) to route traffic over the Internet. See the main page for NAT for more detailed info.