Internet -- Under the Covers
This document is intended to be used to educate people on
how internet software works by introducing the underlying protocols,
how internet software makes use of those, and how to troubleshoot problems
using the underlying protocols. After reading this document and following
the examples, you will be able to, using just a telnet program:
- Post and Read Usenet messages
- Manipulate E-mail messages stored on POP3 servers
- Send E-Mail using SMTP
- Grab portions of webpages using HTTP
In addition, you will be able to:
- Better troubleshoot your email client
- Understand how proxies work
- Understand how some network abuse happens
This section is split into several parts:
Introduction
The Web: The HTTP Protocol
Receiving Mail: The POP3 Protocol
Sending Mail: The SMTP Protocol
Usenet News: The NNTP Protocol
Proxies
DNS
Network Abuse - Omitted
I have omitted the section on Network Abuse here because it contains "open secrets" about the Internet that describe vulnerabilities. Publishing these details would not make me the first, but I am still reluctant to do so. If you need information about how abuse happens, or more detail on any of the protocols, please mail me.
This document written and coded in HTML by Pat Gunn