| What Happens When I Click
Connect? from the May 2000 Actrix Newsletter by Rob Zorn With this brief article I hope to provide you with some
idea of the processes that occur that enable your computer to surf the web or send and
receive email. For the network nitpickers, I know that I have oversimplified and left a
few things out, but my purpose is to help the layperson understand what some of the little
messages mean that they receive whilst dialling in to Actrix or migrating around the
Internet. |
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| Connecting As soon as the two modems have agreed that they understand each other, they will connect and that is what has occurred when you hear the fax-like noises go silent. Once that has occurred, our modem hands you over to our primary authentication server, whose name is Shiva. We also have a secondary authentication server named Satva. Shiva will negotiate with your computer's network settings in order to determine that you are who you say you are (a valid Actrix customer who is entitled to Actrix network access). She'll negotiate an acceptable set of network protocols (usually TCP/IP protocols) which, in simple terms, means that a common language is agreed upon. There are a number of other things Shiva has to establish with your computer before you will be allowed to proceed. She'll assign you an i.p. address which is a set of four numbers separated by full stops such as 203.96.16.119. The i.p. address you are given will be unique to you on the Internet for that session. Records are kept as to exactly who has whatever i.p. address at any given time, and this is one way that people who misbehave on the Internet can be traced. |
 Four Lovely Ladies: |
| Shiva will also assign you the
names of our DNS servers (more on these below), the gateways you are to use and so forth.
Most of that sort of information is carried with you as you travel the net. It takes a few
seconds for all that to be accomplished, and then you are free to go. Browsing So you call up your browser such as Netscape or Internet Explorer and you type an address into your address bar, such as www.yahoo.com. Your browser then shoots that request at our DNS (Domain Name) server who replies with the i.p. address of the requested site. This is because computers don't really understand words very well. They work much better with numbers. So if your browser asks for www.yahoo.com, our DNS server would reply with "204.71.200.75" and this is the "address" your browser would then seek to connect to. This process occurs every single time you move from one site to another on the Internet. |
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| If your browser requests an address that has
not been seen before, our Primary DNS server whose name is Tamas will ask you to wait
while it connects to other DNS servers around the world to find out how to resolve your
request to an i.p. address that your browser's resolver software can use. Once it has done
so, our DNS server caches that information, remembering it for the next person who
requests it. You might be interested to know the general route of your internet surfing. No matter where you are in New Zealand you connect to the internet across the Actrix network. You come down (or up if you're a mainlander) to Wellington where the main gateway out is. From here your internet travel goes through to San Jose in California across the Trans-Pacific cable. From San Jose it goes out to the rest of the world. |
 Our two
chief techies, |
| Email Email travels in a similar fashion. When you finish typing your email and click the Send button, your email software sends it to the Actrix smtp server (mail.actrix.co.nz). Our smtp server uses the email address of your recipient to determine which server around the world your email is destined for. It finds the i.p. address of that server and asks to be allowed to make a TCP connection to it. The recipient mail server checks a number of things, including whether the intended recipient does exist, whether that person is allowed to accept mail, and so forth. When all this has been done, it grants our mail server the permission to squirt the email through. When our mail server receives confirmation that the destination server has accepted the email, the mail is deleted at this end and it is up to the destination server to correctly store and deliver the email to the intended recipient. It can be staggering to think of how many times each day our mail servers make TCP connections to other mail servers around the world! |
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| Of course the reverse is true for email that
comes into Actrix for you. When it has been accepted by our mail server, your email gets
stored in a secure file called your "mailbox" until you connect to request it.
Your email is given to you by the Daemon program that lives on the mail server. When you
connect to it, Daemon talks to the pop (post office protocol) software in your email
program. Your pop software tells Daemon who you are and what your password is. Daemon
checks that you're not pulling his leg and then delivers your email to your email program.
It is then deleted from our server unless your mail program specifically asks for it to
remain. Of course computers don't read words very well. You're probably aware that your email does not travel as words. It travels as numbers (ultimately only as 1s and 0s). Your email program is responsible for turning those numbers back into something that a human could relate to. |
 The Actrix POP3 server |
| Disconnecting When you click the Disconnect button, your computer sends a stop
request to Shiva telling her that you would like to end the session. When she receives
that request, Shiva hangs up, effectively terminating your particular session. That's why
it's important to disconnect correctly from the Internet. |
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