The Internet grew out of the old ARPANET. The ARPANET was created to (1) allow the government to give research institutions only one computer each and let them share computing power, and (2) withstand nuclear missile attacks. The ARPANET was pretty revolutionary; it practically introduced:
In 1969, there were only four hosts
According to Hobbes' Internet Timeline there were over 170 million hosts on the Internet in early 2003. Hobbes' Internet Timeline is required reading.
Big-picture stuff
Technical Stuff
Everything
Nobody runs or controls the net, but there do exist
The three main areas of study regarding internets are:
| Area | Topics |
|---|---|
| Architecture | How the Internet is connected, how the hosts and networks are numbered. The ideas behind packet switching. |
| Protocols | What hosts and other devices say to each other. |
| Services | Those things "end users" find useful. |
The networks on the Internet are pretty much hierarchically organized. To get your data from your PC, Workstation, Handheld, Cellphone, or other device "out there" you pretty much go
Then back down the levels to the destination computer.
ARP, IP, TCP, UDP, HTTP, FTP, SMTP, POP and many, many more.
FTP, Telnet, WWW, Gopher, News, Email. and many, many more.
Sends a message to a remote computer and receives an indication of whether it is alive. May show packet sizes, sequence numbers, round trip times, etc. For example:
PING www.lmu.edu (157.242.56.68) from 10.3.0.7 : 56(84) bytes of data. 64 bytes from www.lmu.edu (157.242.56.68): icmp_seq=0 ttl=116 time=30.414 msec 64 bytes from www.lmu.edu (157.242.56.68): icmp_seq=1 ttl=116 time=20.293 msec 64 bytes from www.lmu.edu (157.242.56.68): icmp_seq=2 ttl=116 time=20.364 msec 64 bytes from www.lmu.edu (157.242.56.68): icmp_seq=3 ttl=116 time=20.420 msec 64 bytes from www.lmu.edu (157.242.56.68): icmp_seq=4 ttl=116 time=20.477 msec --- www.lmu.edu ping statistics --- 5 packets transmitted, 5 packets received, 0% packet loss round-trip min/avg/max/mdev = 20.293/22.393/30.414/4.014 ms
Network people immediately turn to ping when there is a failure in communication. All it can really do is help you figure out which parts of the network are unreachable. ping does not know the difference between a computer that is turned off, a computer with a bad network card, a computer that is not running a ping server, or a computer behind a firewall or other device which filters (eats) ping packets (to prevent flooding attacks).
Displays information on the path (and the final host) together with trip times. For example:
Tracing route to staff.cs.utu.fi [130.232.75.8] over a maximum of 30 hops: 1 9 ms 56 ms 7 ms 10.234.64.1 2 9 ms 8 ms 9 ms cr01-gln1-ca.oc-nod.charterpipeline.net [24.205.0.97] 3 9 ms 10 ms 21 ms er01-mpk1-ca.oc-nod.charterpipeline.net [24.205.1.133] 4 9 ms 9 ms 9 ms bur-edge-02.inet.qwest.net [65.114.177.133] 5 13 ms 15 ms 10 ms bur-core-01.inet.qwest.net [205.171.13.17] 6 15 ms 24 ms 11 ms lax-core-01.inet.qwest.net [205.171.8.41] 7 10 ms 11 ms 12 ms lax-brdr-01.inet.qwest.net [205.171.19.38] 8 16 ms 12 ms 12 ms pos6-0.core1.LosAngeles1.Level3.net [209.0.227.41] 9 14 ms 12 ms 13 ms so-4-3-0.mp1.LosAngeles1.level3.net [209.247.9.141] 10 94 ms 71 ms 73 ms so-0-0-0.bbr2.Washington1.level3.net [64.159.1.158] 11 189 ms 144 ms 145 ms so-0-0-0.mp2.London2.Level3.net [212.187.128.133] 12 180 ms 181 ms 180 ms so-4-1-0.mpls1.Stockholm1.Level3.net [212.187.128.218] 13 181 ms 181 ms 181 ms 213.242.68.67 14 179 ms * 179 ms 213.242.69.18 15 184 ms 184 ms 183 ms fi-gw.nordu.net [193.10.68.42] 16 182 ms 182 ms 185 ms funet1-rtr.nordu.net [193.10.252.50] 17 185 ms 185 ms 188 ms abo0-p000-csc0.funet.fi [193.166.255.162] 18 184 ms 184 ms 184 ms abo3-g0000-abo0.funet.fi [193.166.187.22] 19 185 ms 186 ms 185 ms e2-funet.utu.fi [130.232.202.214] 20 186 ms 208 ms 187 ms kenny-ext.utu.fi [130.232.202.65] 21 189 ms 207 ms 187 ms kh2-sgext.rs.utu.fi [130.232.202.45] 22 210 ms 186 ms 188 ms multinet-rtr-alpine1.utu.fi [130.232.202.222] 23 186 ms 186 ms 187 ms staff.cs.utu.fi [130.232.75.8]
Some machines have traceroute disabled to prevent flooding attacks.
See traceroute.org for a list of links to sites that have made traceroute services from their hosts available to you on the web.
The domain information groper. Performs name to address lookups by querying DNS servers. Similar commands include nslookup and host.
Gives information on your machine's Internet connection and activity. Displays network connections, routing tables, interface statistics, masquerade connections, netlink messages, and multicast messages.