What's New!

Chat with
Hackers

How to Defend
Your Computer 

The Guides
to (mostly) 
Harmless Hacking

Happy Hacker 
Digests (old stuff) 

Hacker Links 

Hacker
Wargames 

Meet the 
Happy Hacksters 

Help for 
Beginners 

Hacker 
Bookstore 

Humor 

It Sucks 
to Be Me!

How to Commit
Computer Crime (not)! 

What Is a 
Hacker, Anyhow? 

Have a 
Great Life! 

News from the 
Hacker War Front

More Internet for Dummies...

In fact, many ISPs use nothing more than networked PCs running Linux!

As a result, all the computing, data storage, and sending, receiving and forwarding of messages on the Internet is handled by the millions of computers of many types and owned by countless companies, educational institutions, governmental entities and even individuals.

Each of these computers has an individual address which enables it to be reached through the Internet if hooked up to a appropriate communications link. This address may be represented in two ways: as a name or a number.

The communications links of the Internet are also owned and maintained in the same anarchic fashion as the hosts. Each owner of an Internet host is responsible for finding and paying for a communications link that will get that host tied in with at least one other host. Communications links may be as simple as a phone line, a wireless data link such as cellular digital packet data, or as complicated as a high speed fiber optic link. As long as the communications link can use TCP/IP or UUCP, it can fit into the Internet.

Thus the net grows with no overall coordination. A new owner of an Internet host need only get permission to tie into one communications link to one other host. Alternatively, if the provider of the communications link decides this host is, for example, a haven for spammers, it can cut this “rogue site” off of the Internet. The rogue site then must snooker some other communications link into tying it into the Internet again.

The way most of these interconnected computers and communications links work is through the common language of the TCP/IP protocol. Basically, TCP/IP breaks any Internet communication into discrete "packets." Each packet includes information on how to rout it, error correction, and the addresses of the sender and recipient. The idea is that if a packet is lost, the sender will know it and resend the packet. Each packet is then launched into the Internet. This network may automatically choose a route from node to node for each packet using whatever is available at the time, and reassembles the packets into the complete message at the computer to which it was addressed.

These packets may follow tortuous routes. For example, one packet may go from a node in Boston to Amsterdam and back to the US for final destination in Houston, while another packet from the same message might be routed through Tokyo and Athens, and so on. Usually, however, the communications links are not nearly so torturous. Communications links may include fiber optics, phone lines and satellites.

The strength of this packet-switched network is that most messages will automatically get through despite heavy message traffic congestion and many communications links being out of service. The disadvantage is that messages may simply disappear within the system. It also may be difficult to reach desired computers if too many communications links are unavailable at the time.

However, all these wonderful features are also profoundly hackable. The Internet is robust enough to survive -- so its inventors claim -- even nuclear war. Yet it is also so weak that with only a little bit of instruction, it is possible to learn how to seriously spoof the system (forged email) or even temporarily put out of commission other people's Internet host computers (flood pinging, for example.)

On the other hand, the headers on the packets that carry hacking commands will give away the account information from which a hacker is operating. For this reason it is hard to hide perfectly when on the Internet.

It is this tension between this power and robustness and weakness and potential for confusion that makes the Internet a hacker playground.

For example, HERE IS YOUR HACKER TIP YOU’VE BEEN WAITING FOR THIS ISSUE:

ftp://ftp.secnet.com

This ftp site was posted on the BUGTRAQ list, which is dedicated to discussion of Unix security holes. Moderator is Aleph One, who is a genuine Uberhacker. If you want to subscribe to the BUGTRAQ, email LISTSERV@netspace.org with message “subscribe BUGTRAQ.”

Now, back to Internet basics.

History of Internet

As mentioned above, the Internet was born as a US Advanced Research Projects Agency (ARPA) effort in 1969. Its inventors called it ARPANET. But because of its value in scientific research, the US National Science Foundation (NSF) took it over in 1983. But over the years since then it gradually evolved away from any single source of control. In April 1995 NSF cut the last apron strings. Now the Internet is run by no one. It just happens and grows out of the efforts of those who play with it and struggle with the software and hardware.

Nothing at all like this has ever happened before. We now have a computer system with a life of its own. We, as hackers, form a big part of the mutation engine that keeps the Internet evolving and growing stronger. We also form a big part of the immune system of this exotic creature.

The original idea of ARPANET was to design a computer and communications network that would eventually become so redundant, so robust, and so able to operate without centralized control, that it could even survive nuclear war. What also happened was that ARPANET evolved into a being that has survived the end of government funding without even a blip in its growth. Thus its anarchic offspring, the Internet, has succeeded beyond the wildest dreams of its original architects.

The Internet has grown explosively, with no end in sight. At its inception as ARPANET it held only 4 hosts. A quarter of a century later, in 1984, it contained only 1000 hosts. But over the next 5 years this number grew tenfold to 10,000 (1989). Over the following 4 years it grew another tenfold to 1 million (1993). Two years later, at the end of 1995, the Internet was estimated to have at least 6 million host computers. There are probably over 10 million now. There appears to be no end in sight yet to the incredible growth of this mutant child of ARPANET.

In fact, one concern raised by the exponential growth in the Internet is that demand may eventually far outrace capacity. Because now no entity owns or controls the Internet, if the capacity of the communications links among nodes is too small, and it were to become seriously bogged down, it might be difficult to fix the problem.

For example, in 1988, Robert Morris, Jr. unleashed a "virus"-type program on the Internet commonly known as the “Morris Worm.” This virus would make copies of itself on whatever computer it was on and then send copies over communications links to other Internet hosts. (It used a bug in sendmail that allowed access to root, allowing the virus to act as the superuser).

Quickly the exponential spread of this virus made the Internet collapse from the communications traffic and disk space it tied up.

More Internet for Dummies --->


Carolyn's most
popular book,
in 4th edition now!
For advanced
hacker studies,
read Carolyn's
Google Groups
Subscribe to Happy Hacker
Email:
Visit this group

 

Return to the index of Guides to (mostly) Harmless Hacking!

 © 2013 Happy Hacker All rights reserved.