The Internet can best be described as network of data networks with millions of users, spanning the entire globe. Opera accesses the Internet using the World Wide Web (WWW) to retrieve information.
Having its origin in the military, the Net is now undergoing fundamental changes. Business has discovered it as a medium to transfer information quickly and cost-effectively. But as an inherently one-to-one communication medium, it also holds enormous potential for marketing in companies big or small.
The Internet is linked via satellite and undersea cables. The "host" or "server", the core of individual networks, usually carries all the information of the "clients", and make them available to anyone in the world who is "online". This allows the "clients" to be "offline", means their information is still accessible from the "server".
Picture it as your right hand as the server, and your fingers as individual
clients; the body is the world, and your other hand or foot is just another
server. But now you don't only have two hands and two feet, but thousands
of them, each one with hundreds or thousands of fingers and toes. And if
one foot is bathing, means temporarily "offline", others will ensure that
information crossing the body is still delivered via another route until
the server is up again. This is the Internet - big, fast, flexible.
World Wide Web
The World Wide Web is an information system that makes it possible to navigate through the Internet in a simple fashion by clicking on what are known as 'links'. You can access documents, files, programs and applications via the WWW - or short: "web'.
Lately, technology has made it possible to also 'stream' information to your
PC. This means you no longer have to download the complete file and play/run
it on your side, but you get piece by piece sent to your PC, and you can
use it as it is sent. In practice, this means you can listen to the first
20 seconds of a -- say -- RealAudio file, and then abort the transfer whenever
you like. The information is used as it is received, therefore a 'stream'
of data.
Electronic mail
Email is probably the most versatile and effective element of modern communications technology. It allows you to communicate with friends, relatives or like-minded souls quickly and cost-effectively.
Email is split into SMTP and POP3. SMTP (Simple Mail Transfer Protocol) is for sending mail; POP (Post Office Protocol) is used for receiving messages.
Opera has support for sending electronic mail messages; it cannot receive mail at the moment. Before you can send messages from Opera, you must specify your name, the machine you will use to send mail (mail server), and finally your mail address. The address must be in the format
name@address.country
ie. SMTP format.
Note: You can ask your system administrator or Internet supplier for the name of your mail server.
If you already have a mail program you can use this with Opera. Specify this
program instead of your name, mail server and mail address.
Newsgroups (USENET)
USENET or newsgroups is a 'place' in cyberspace where people with common interests share discussion forums. Anything from the absurd to the bizarre, from politics to computers, from hobbies to interests, from the present to the future is being discussed. There are currently more than 20.000 individual newsgroups listed. Have your pick, and take part in inter-continental communication. Subscription is free in most cases. Please refer to the group:
news.announce.newusers
for details on how to conduct in the news- or discussion forums.
On the public USENET, technical questions relating to Opera and other browsers are discussed under
comp.infosystems.www.browsers.ms-windows
Otherwise, please visit this online
home page link to
our own news server
Addresses
Opera is a programme which provides access to the World Wide Web World_Wide_Web(WWW). WWW uses a type of address known as Universal Resource Locator (URL). These are some examples of URLs:
http://www.operasoftware.com/index.html
ftp://is.co.za
news:no.marked
Usually a URL consists of the following sections:
protocol://machine-name/directory/filename
but in some cases particular sections can be omitted.
Protocols
A protocol states how a document shall be retrieved, and what type of document it is. Opera supports the following protocols:
HTTP - HyperText Transfer Protocol. This is the most common protocol and is used for retrieving normal documents on the Web.
FTP - File Transfer Protocol. This is used for retrieving simple documents, files and programmes from so-called FTP (FTP-file-stores).
Gopher - This is used for searching for files in large archives of documents.
WAIS - Wide Area Information Server.
News - This is used for reading newsgroups (discussion groups).
Mailto - This is used for sending electronic mail.
Links can usually be seen as differently coloured text, eg.red. But links can also be graphics, and these have an extra border round them, which is usually red. The colour can be selected in the 'Preferences' menu, under 'Link Presentation'. When you click on a link, you retrieve the document the link points to.
You can now also save files that are links, like .MIDI files. This is being
done via the right-click menu.
Winsock
Winsock is a programme library, which is used for communications. Opera is dependent on this library for retrieving information from the Internet.
Problems with different communications modules
(winsock)
There are very many different communications modules (winsock) available.
Sometimes these can be very different in the problems produced. In the worst
case the machine can hang. In order to solve this problem Opera has some
choices under Advanced Preferences which
can be worth trying if the programme does not behave as expected.
In some cases Opera must be set to use Synchronous Domain Name Service (DNS). If you are using Microsoft's Winsock 2.x upgrade, you may have to run Opera with Synchronous DNS enabled. This may make Opera somewhat slower. It also must often be chosen if you use PC-NFS 5.1 or Microsoft TCP/IP.
If you use PC-NFS 5.0, you may have to upgrade some modules of that system, as well as set the network buffer size to 1 kB.
If you have tried to set Synchronous DNS, and the network buffer to 1 kB or a higher value (eg. 20 kB) without success, you can also try setting down total connections to 1, for both combined and a single server. This makes Opera slower, but also behave better when using the communications module.
A Name server is like a telephone directory. Give it a name/address and it finds the corresponding number.
In practice, if you enter a URL (uniform resource locator) like
http://www.operasoftware.com, the name server will look up the IP (Internet
Protocol) address relating to that URL. This will tell the server to look
up Opera Software's server and retrieve its documents.
MIME
The MIME protocol is a method for declaring document types. It is used when
sending mail over the Internet or World Wide Web. When Opera retrieves a
document it checks the document type and whether it can display it. If Opera
does not know how to display it, the user is asked to decide what should
happen - whether it should be saved or displayed with another programme.
HTML
HTML - Hyper Text Markup Language is a readable document format which is used on the World Wide Web.
An example of HTML is shown below:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN">
<HTML>
<HEAD>
<TITLE>Welcome to our home page</TITLE>
<META NAME="GENERATOR" CONTENT="Arachnophilia Version 2.5">
<META NAME="FORMATTER" CONTENT="Arachnophilia Version 2.5">
</HEAD>
<BODY BACKGROUND="" BGCOLOR="#000000" TEXT="#ffffff" LINK="#ff80ff"
VLINK="#80ff80" ALINK="#b30000">
<P>
<H1>This is a header</H1>
This is body text. And this is <B>bold</B>.
Here is a <A HREF="tips.htm">link.</A>
</BODY>
</HTML>
On the web, this would look like this:
This is body text. And this is bold.
Here is a link
As you can see, HTML is a markup language, governed by tags in brackets <>.
This makes it easy to write HTML documents, but the newer word processors
and HTML editors take the pain out of writing HTML code manually.
TCP/IP
TCP (Transmission Control Protocol) is the protocol that defines how to transmit data and reliably deliver them, or detect and recover from a failure.
IP is the Internet Protocol, defining how to transmit a chunk of data from one computer to another via a number of connected networks.
TCP breaks up the message it will send into smaller packets, which IP then
gets to its destination, and the remote TCP then reconstructs the message
and delivers it, or handles any problems before it can deliver the message
to the receiver.
SSL / TLS
The TLS (Transport Layer Security) Protocol is the result of further development based on the SSL (Secure Sockets Layer) version 3.0 (developed by Netscape).
The development has been made by a Work Group in the Internet Engineering Task Force (IETF) over the last couple of years. TLS has now been accepted as a Proposed Standard by the standards group overseeing internet standards.
The message structure is mostly the same as in SSL v3, but many of the fundamental (cryptographical) formulas used to calculate encryption keys and so on has been changed to improve security.
The protocol is designed to let a client (browser, in our case) and a server, to agree on a method of encrypted communication, optionally verify each others identities, exchange secret information needed to create encryption keys. The messages sent between the client and the server are then encrypted using the agreed upon keys. Each part of the message contains a signature verifiying the authenticity of the message part (the signature is *very* difficult to counterfeit without knowing the secret exchanged when the connection was set up.
If you are interested in more information, take a look at the IETF TLS WG home page http://www.consensus.com/ietf-tls/ or the SSL talk FAQ at http://www.consensus.com/security/ssl-talk-faq.html
Why do I have to press "Accept" when I do my online banking?
The certificates you have to press accept on, are either registered with
a warning in the database, or as I think is the problem in your case, not
traceable to a certificate in the database. The certificates from RSA Data
security, secure server and commercial, which you most likely lacked is included
in the beta.
Some technical info
There are two types of certificate chains a server can send you, an incomplete
one, without the root certificates, or complete ones, with root certificates.
All certificate chain shall be traceable to a root certificate, which can then be verified with its own public key (other certificates are verified using the public key of the issuers certificate, next in the chain).
If the certificate chain sent by the server is complete and the root certificate is in the database, or if the issuer of the last certificate in the chain is registered in the database, all is well (provided warning/deny is not set).
If the root certificate, or the issuer of the last certificate, are not registered, a warning is issued, asking the user if he wants to accept the connection. If the chain is complete the user is given the option of installing the root certificate, otherwise the new beta will remember the server's certificate and accept it for that run of Opera, as opposed to this negotiated session as in your version.
If you encountered the accept on every image, or page from a server, those
who run that site did not set it up properly, or they are not closing the
connection properly, or, as is their right, they set it up to not use what
is called session resumption. Session resumption reuses the shared secrets
used to create the encryption keys negotiated in a previous connection, saving
the time needed to exchange the necessary data, and reducing the computational
load on the server.
Javascript
Cautions
Because of the interactivity between Javascript and your computer, and the
fact that Javascript is executed on your computer and not the host
computer, it may come to undesired effects, and in the worst case to crashes.
Also, due to the nature of Javascript, it is not a safe 'language', so we caution you against possible side-effects.
You may be asking yourself why we have implemented Javascript if it poses certain risks to your computer. The answer is that more and more site use it for enhanced navigation, as well as 'interactivity' of their pages. This is true for commercial as for private sites.
If you are uncomfortable with Javascript, disable it. You can do so via Preferences/Multimedia.
Below please find a very brief introduction on Javascript.
Examples
JavaScript code is embedded directly into the HTML-page. In order to see
how this works we are going to look at an easy example:
<html> <body>
This is a normal HTML document.
<script language="JavaScript"> document.write("This is JavaScript!") </script>
Back in HTML again. </body> </html>
At the first glance this looks like a normal HTML-file. The only new thing
is the part:
<script language="JavaScript">
document.write("This is JavaScript!")
</script>
This is JavaScript. In order to see this script working save this code as
a normal HTML-file and load it into your JavaScript-enabled browser.
Here is the output generated by the file (if you are using a JavaScript browser
you will see 3 lines of output):
This is a normal HTML document.
Back in HTML again.
I must admit that this script isn't very useful - this could have been written in pure HTML more easily. I only wanted to demonstrate the <script:gt; tag to you. Everything between the <script> and the </script;> tag is interpreted as JavaScript code. There you see the use of document.write() - one of the most important commands in JavaScript programming. document.write() is used in order to write something to the actual document (in this case this is the HTML-document). So our little JavaScript program writes the text This is JavaScript! to the HTML-document.
What does our page look like if the browser does not understand JavaScript? A non-JavaScript browser does not know the <script> tag. It ignores the tag and outputs all following code as if it was normal text. This means the user will see the JavaScript-code of our program inside the HTML-document. This was certainly not our intention. There is a way for hiding the source code from older browsers. We will use the HTML-comments <!-- -->. Our new source code looks like this:
<html>
<body>
<br>
This is a normal HTML document.
<br>
<script language="JavaScript">
<!-- hide from old browsers
document.write("This is JavaScript!")
// -->
</script>
<br>
Back in HTML again.
</body>
</html>
The output in a non-JavaScript browser will then look like this:
This is a normal HTML document. Back in HTML again.
Without the HTML-comment the output of the script in a non-JavaScript browser would be:
This is a normal HTML document.
document.write("This is JavaScript!")
Back in HTML again.
Please note that you cannot hide the JavaScript source code completely. What we do here is to prevent the output of the code in old browsers - but the user can see the code through 'View document source' nevertheless. There is no way to hinder someone from viewing your source code (in order to see how a certain effect is done).