Chapter 1, Introducing Networks and Protocols

1. What are the key differences between IPv4 and IPv6?

IPv4 only supports 4 billion unique addresses, and because they were allocated inefficiently, we are now running out. IPv6 supports 3.4 x 10³⁸ possible addresses. IPv6 provides many other improvements, but this is the one that affects our network programming directly.

2. Are the IP addresses given by the ipconfig and ifconfig commands the same IP addresses that a remote web server sees if you connect to it?

Sometimes, these addresses will match, but not always. If you're on a private IPv4 network, then your router likely performs network address translation. The remote web server then sees the translated address.
If you have a publicly routable IPv4 or IPv6 address, then the address seen by the remote web server will match those reported...