Configuring Internet Access

Understanding the Internet

The Internet was originally created and implemented by DARPA (Defense Advanced Research Projects Agency; often referred to as just ARPA) in response to a U.S. Department of Defense (DoD) request. At the time, the DoD was concerned about its centralized communications network. Most communications were relayed through a central computing system or hub, and damage to that system could stop computer communication. To avoid this problem, the DoD gave ARPA the responsibility of devising a new system.

The first thing that ARPA had to do was to create communication protocols that would allow computers to talk to each other in a new and nonstandard, decentralized manner, and ARPA needed a small network on which it could test and develop the new protocols. It eventually interconnected four hosts, which formed the start of the ARPANET.

ARPANET (and now the Internet) was defined by a series of standards that are currently being put forth by the Internet Architecture Board (IAB), which represents the governing body of the Internet. These Internet standards are defined by IAB but are discussed in RFC (Request for Comments) documents. The first RFC defined how the initial hosts on the ARPANET would send to and receive data from each other.

All RFCs — currently, more than 5,500 — are available from www.ietf.org. Technologies in RFCs sometimes make it into STD (Standards) documents, of which there are currently fewer than 70. An index of the standards can be found at

www.rfc-editor.org/std-index.html

During the 1970s, protocols were created and evolved, allowing for support of more and more services over ARPANET, and the number of members continued to increase. Most ARPANET members were locations that did research for ARPA — mainly universities and research centers. Terminal connections via Telnet were created, as was the fashion of using the @ character (meaning at) as a separator between username and mail server for email addresses. Emoticons were soon to follow, starting with joke markers, such as -) (tongue in cheek) in the late 1970s, and the first smileys :-) in the early 1980s. Now we have emoji icons that are little yellow icons showing different emotions and expressions and sometimes hand signals like a thumbs up.

During the 1980s, several major events occurred:

TCP/IP became the standard communication protocol.
The term Internetwork, truncated to just Internet, became the name of the network.
Many operating systems standardized on TCP/IP.
The National Science Foundation took over management of the Internet.
The IAB was established to manage accepted standards on the Internet.

Also during 1980s, other countries started to join their national networks to the U.S. Internet, making it a true world-wide network. Several new application protocols were created to allow communication, such as NNTP (Network News Transfer Protocol) and IRC (Internet Relay Chat). This was also the decade that saw the first Internet worm released — namely, the Morris Worm, which was named for its creator.

TCP/IP — Transmission Control Protocol/Internet Protocol — is the protocol suite that is used by the Internet, but it comprises many different protocols that function at different levels of the network model. There are network protocols, transport protocols, and application protocols. In fact, the number of protocols is limitless. Many key protocols are discussed in earlier chapters (see Book 7, Chapter 3, and Book 8, Chapter 1), but this chapter covers some of the others, such as

SMTP: Simple Mail Transport Protocol
POP3: Post Office Protocol version 3
HTTP: Hypertext Transfer Protocol
FTP: File Transfer Protocol
IMAP: Internet Message Access Protocol

TCP/IP — the communication protocol used on the Internet — is actually a suite of protocols that covers all aspects of the communication process.

In the 1990s, the biggest single change to the Internet was caused by CERN (Conseil Européen pour la Recherche Nucléaire, or the European Council for Nuclear Research) developing a new method of linking documents stored on different servers. CERN modified SGML (Standard Generalized Markup Language), created a new language called HTML (Hypertext Markup Language), and named the technology the World Wide Web. This single technology changed the face of the Internet, which went from a method of linking documents for information to a conduit for shopping, personal expression, media production and delivery, and untold other things.

Since 2000, technologies created for and used over the Internet have steadily risen to allow for remote access, collaboration, file sharing, streaming media, and VoIP (Voice over Internet Protocol). Government services and major corporations have all embraced the Internet as a major method of communicating with clients, and people in general have changed how they communicate, using instant messaging and social networking sites. Internet gaming has become popular, with software companies generating steady revenue streams from monthly gaming fees. Today, if the Internet disappeared, many people would be at a loss to figure out how to communicate with one another.

Many countries now offer public access terminals for the Internet in convenient locations, such as libraries. Users can connect to the Internet through these public access terminals, WiFi hot spots, and any number of other methods. Some cities have gone so far as to set up city-wide public wireless access.

The Internet has evolved from something small to become what we now know as the Internet. Even today, the Internet is constantly evolving, with new protocols created daily and new uses for the technology limited only by imagination. I wonder what the Internet will look like by the end of the next decade.

Understanding Internet Protocols

When many people think of protocols and computers, network and transport protocols come to mind. These two types of protocols seem to get all the credit. Network and transport protocols are the network communications components that connect your computer to a network, sending and receiving bundles of data between hosts. TCP/IP is the main protocol found today on networks.

Generically, a protocol is a set of standards or conventions that are followed when formatting data to be used for electronic communications, and data transfer is just one level in the electronic communications model. This definition of protocol is not limited to data transfer, and a number of protocols work at other layers: most notably, the application layer. Application layer protocols establish a standard or format for data that is to be communicated. These protocols are so-named because they are the first layer to which programs or applications on a computer (as well as the server components) communicate.

TCP/IP

TCP/IP is not a protocol in and of itself; rather, it is a suite of industry-standard protocols. It is a routable protocol that is used for communication on the LAN or across networks. TCP/IP standards are developed, established, and used by the computing community itself.

Figure 4-2 shows some protocols used as part of the TCP/IP protocol suite and what each protocol is responsible for. At the lowest level, IP offers best-effort delivery services. That is, IP attempts to deliver all network packets to the best of its ability. It also processes any errors reported back from routers. At the next level, TCP offers guaranteed delivery services, and UDP (User Datagram Protocol) offers best-effort delivery services.

FIGURE 4-2: TCP/IP uses many protocols at different layers to accomplish its task.

Session services for TCP/IP are offered by either NetBIOS over TCP/IP (NetBT) or Windows Sockets (Winsock). The NetBIOS session interface is used by all Microsoft network clients as their method of communicating with Microsoft servers on the network. The Winsock interface is Microsoft’s implementation of BSD sockets, which is the primary session interface that has been used on all UNIX and UNIX-based systems. Because most Internet servers originally ran UNIX, the application layer protocols (such as HTTP, FTP, SMTP, and POP3) are all designed to communicate through the socket-based session interface.

Email

Email is one of the applications that made the Internet indispensable to most people. Email was an early tool for ARPANET that enabled users to communicate ideas and concepts to colleagues many miles away. Email allows for individually addressed text messages to be transferred over the Internet and delivered directly to the targeted recipient(s). Compared with conventional land-based mail (snail-mail), these transfers are instantaneous.

Attachments that accompany email messages are converted into a text stream by means of encoding. MIME (Multipurpose Internet Mail Extensions) is currently one of the most popular encoding methods on the Internet. Other popular encoding formats include BinHex and UUencode. Encoding, which converts binary data containing 8 bits per byte to ASCII or text data with 7 bits per byte, enables binary attachments to be sent over the text-based email network. When you receive attachments, they must be decoded by your email program. If your email program cannot do this, however, you have to use a third-party application to decode the files.

When it comes to reading your email, you can choose from a wide variety of applications. In fact, the list of clients is extensive, including command line clients, Windows-based clients, and web-based clients.

The three basic protocols used with email are POP3, SMTP, and IMAP:

SMTP is the Internet protocol used to send email.
POP3 and IMAP are the Internet protocols used to receive email.

Some email clients may support more than one access protocol. SMTP and POP3 are the most commonly used protocols although IMAP is increasing in popularity on private networks. Figure 4-3 shows how these three protocols fit together, and the following sections discuss them in more detail.

FIGURE 4-3: Where mail protocols are used.

SMTP

Simple Mail Transport Protocol (SMTP) is a mail delivery protocol, used to transfer mail messages from your mail client to a mail server. After the mail message is in queue on the server, SMTP is also used to transfer the message to the mail server that is responsible for the target domain, such as @gleneclarke.com. The primary goal of SMTP is to get the mail messages to the server that hosts email for that domain.

POP3

Post Office Protocol version 3 (POP3) is a client access protocol, used to access or retrieve mail from a server. POP3 does not send email — that is the responsibility of the SMTP. When you configure your email client, you will configure it with the pair of servers: POP3 for downloading or reading, and SMTP for sending (see the preceding section). POP3 clients usually download all mail messages for their servers and delete the mail from the server. This action then leaves the mail only on the client computer.

IMAP

Internet Message Access Protocol (IMAP) is also a client access protocol for mail. As an IMAP client, you retrieve a list of messages that exist on the mail server and download only messages that you want to read. Any downloaded messages are also left on the server. Changes to your mail files locally can also be replicated to the server. Because you can download all messages, you can work entirely offline. If you delete messages while working offline, those deletions will be replicated to the server the next time you connect, in turn deleting the messages on the server.

Configuring an email client

When you want to read email, you must first configure an email program on your system. This email program is also known as an email client because it connects to the service provider’s email server and downloads the email to your system using POP3 or IMAP.

There are a number of email programs you can use as a POP3 client and configure to connect to the ISP’s email server. You can use the popular Microsoft Outlook, or use a free program such as Opera Mail.

To make this connection with an email client, you need the following information:

Username: The username is provided by the service provider and most times may be the first part of your email address. For example, the account bobsmith@myisp.com would most likely have a username of bobsmith.
Password: The password is supplied by the ISP when it created your account. Make sure that you change that password so that no one can easily guess the password.
SMTP Server (outgoing server): This is the address of the server that will send emails for you. You can input the IP address or the FQDN of the server, such as mail.myisp.com or smtp.myisp.com.
POP3/IMAP Server (incoming server): This is the address of the server that you download your emails from. It is most likely the same system as the SMTP server that sends your emails. Again, you can use the IP address or the FQDN of the server, such as mail.myisp.com or smtp.myisp.com.

The following steps demonstrate how to configure the Outlook 2016 client as a POP3 client:

Launch Outlook by clicking the icon on the Taskbar and then choose Next on the Welcome to Outlook 2016 screen.
Choose Yes to set up Outlook to connect to an email account and then choose Next.
Choose Manual setup or additional server types in order to specify your POP3 and SMTP server settings along with your email account information.
Choose POP or IMAP as the service type and then choose Next.
Fill in your user information such as your name and email address.
In the Server Information area, specify whether you are using POP3 or IMAP to connect to the mail server and download the mail.

You will most likely use POP3.
Type the address of your POP3 server (Incoming mail server) and SMTP server (Outgoing mail server), as shown in Figure 4-4.

You are asked for your account name and password. You will need to get this information from the email provider.
In the Login Information section, provide your username and password and then select Remember Password.
Choose Next and then Finish.

FIGURE 4-4: Configuring SMTP and POP3 server settings.

When configuring email software, you may need to specify other configuration settings depending on the software you are configuring. Following are some common settings that may need to be configured:

Port and SSL settings: You may need to configure the email client port for nonsecure and secure (SSL) email:
- For nonsecure email, the default port is 110 for POP3 and 143 for IMAP.
- For secure (SSL) email access, the ports are 995 for secure POP3 over SSL and 993 for secure IMAP over SSL.
Exchange: You may need to connect your email software to the company Exchange server. Microsoft Exchange Server is the name of the Microsoft mail server product that companies use to host their own email. To connect to the Exchange server from Outlook, you need to specify
- The name of the Exchange server
- The mailbox name you want to connect to
Gmail: Many people are using online email providers such as Hotmail and Gmail to access their email over HTTP. You can configure most email software to connect to the Hotmail or Gmail mailboxes by just typing in the email address of the account.

Web mail accounts, such as Hotmail and Gmail, have become increasingly popular over using POP3 and IMAP. These accounts leave their mail messages on the server in a manner similar to IMAP.

Hypertext Transport Protocol

Much older than the Internet, the concept of hypertext has been around since 1945 when Vannevar Bush wrote an article titled “As We May Think.” The word hypertext was coined in 1965 by Ted Nelson. Hypertext was a means of indexing, or cross-referencing, data found in different documents, allowing users to quickly move to linked documents.

In the early days of the Internet, you could transfer data as files between computers. After being uploaded to the server by the data owner, these files were available for download from those servers, which meant you had to know what files you needed and what servers they came from. Your text files, formatted documents, and graphics could be transferred between computers. After you downloaded the files, they could be opened and viewed, but there was no way to view them in an attractively formatted style in the online environment, especially in a format that was universally accessible. Most formatted documents were created and formatted in proprietary programs like Microsoft Word or Adobe PageMaker — and thus readable only by people who have those programs.

To address the problem of knowing which servers you were accessing data from, Paul Lindner and Mark McCahill (University of Minnesota) came up with an idea that became the Gopher protocol in 1991. Gopher used hypertext concepts and allowed you to place a pointer on your server that would connect people to specific directories on other servers elsewhere on the Internet. This made browsing information scattered across servers very easy because switching between servers became completely transparent. Gopher became the most popular tool for downloading files and data from the Internet.

At the same time Gopher was being developed, the researcher Tim Berners-Lee at CERN was working on a hypertext system he called World Wide Web (choosing that name over The Information Mesh). This system implemented a protocol called HTTP, which allowed for transparent linking of documents between servers. This capability was possibly thanks to the new Hypertext Markup Language (HTML) that was being used for World Wide Web data.

The tool that accesses HTTP servers and HTML files is, of course, the web browser. A web browser retrieves the files from the server, displays the formatted document, and links to other servers as required. Early web browsers displayed text and images as separate but linked documents, so you could view images if you followed an image link. The web really took off in 1993 when Marc Andreessen of the National Center for Supercomputing Applications (NCSA) released NCSA Mosaic and offered something the Gopher and other web browsers lacked — the capability to view text and graphics mixed together in a single frame. Internet users flocked to this new technology that gave their data the same appearance as the paper-bound copies. Figure 4-5 shows a formatted document in a web browser.

FIGURE 4-5: Web browsers let you retrieve data from a server using HTTP.

Hypertext Markup Language

Hypertext Markup Language (HTML) is a form of SGML that offers a universal way to format documents. Standards for SGML are more complex than for HTML. SGML is actually a method of creating interchangeable, structured documents so that they can be universally accessed from different types of systems. SGML can take data from a variety of sources (such as word processors and graphics applications) and join them as a single structured document by using Document Type Definitions (DTDs). Different DTDs are identified in a document with the aid of markups or tags, which show or identify the divisions or sections.

HTML is actually just a DTD that is one of the many small parts of SGML. With the simple initial requirements for formatting of documents, Tim Berners-Lee decided that keeping the formatting language simple was the best course of action for the web, so HTML was adopted in favor of SGML.

HTML files are text or ASCII files, but they contain formatting codes that are embedded in the text. The web, or HTML, page displayed in Figure 4-5 was generated with the following script (Listing 4-1).

LISTING 4-1: Script used to create the web page shown in Figure 4-5

<html> <head><title>A+ Sample Web Page</title> </head> <body> <h1>Web Page Basics</h1> <p>The web page is the basics of HTML.</p> <p>It does require that somebody has to do a lot of typing to create the web content. This content has formatting tags embedded in the content, which suggest how to draw items on the page. The decision of how to actually draw or render the content is actually made by the client browser.</p> <hr> <img src="photo.jpg" width="320" height="176" align="right"> Some different client browsers include: <ul> <li>Internet Explorer <li>Mozilla Firefox <li>Cello <li>etc </ul> </body> </html>

Early HTML files were saved with either the .html or .htm extension, but now may have a variety of extensions (such as .php or .asp) because of various scripting languages being used to build dynamic web pages.

HTML has gone through many revisions; the last revision was version 4. Changes are being made to HTML with the integration of XML (Extensible Markup Language). XML, which adds functionality to support database data exchange, is designed to transfer not only sections of data from a database but also its structure. XML has become very popular and is a huge Internet buzzword.

As I mention, XML has been rolled into the HTML standard, forming the XHTML (Extensible Hypertext Markup Language) standard, so HTML is now XHTML. The current version of XHTML is 1.0, with 2.0 just around the corner with a working draft already in place. For more information about XML, HTML, and XHTML standards, visit the World Wide Web Consortium at www.w3.org.

HTTPS and SSL

HTTPS is a secure version of the Hypertext Transport Protocol. When you use HTTP, all communication between you and the server is in cleartext, so anyone can easily read all that communication. HTTPS uses SSL (Secure Sockets Layer) or its successor, TLS (Transport Layer Security), to provide authentication and encryption services.

HTTP communicates with a server on TCP port 80, and HTTPS uses TCP port 443.

To implement SSL, a web server needs to have a security certificate installed to verify its identity for you. When you are confident that the server is who it says it is, you can then carry out secure and encrypted data transfers with it.

Early SSL used 40-bit encryption keys, which were not secure and were easy to break. Current SSL uses 128-bit or larger keys and is very hard to break, making data protected with SSL very secure.

Do not confuse the flurry of H-based acronyms used for the World Wide Web. HTML is the document formatting; HTTP is the cleartext transfer protocol that uses TCP port 80; and HTTPS is an encrypted transfer protocol — secured by SSL or TLS — which uses TCP port 443.

File Transfer Protocol

The first scientists using the Internet established early during the evolution of the Internet that there would have to be some format to allow for the transfer of data (as opposed to text messages) across the Internet. The solution was File Transfer Protocol (FTP), which allows files to be uploaded and downloaded from servers. FTP requires an accessible directory or folder, a server-side service (or daemon), and a client.

There are a large number of FTP clients to choose from, ranging from command line–based to graphical (like FileZilla or WinSCP). Figure 4-6 shows some different FTP clients available on the Windows platform. If you regularly work with FTP, then you will likely want to learn one of these clients, rather than relying on the FTP features that are included with most web browsers.

FIGURE 4-6: Choosing the right client for the job is important.

Because of the method that traditional FTP servers used, they were not Network Address Translation (NAT) friendly when the server was placed behind a NAT gateway or firewall. That led to the creation of passive FTP, which changes the orientation of connections in the FTP process. To make use of a passive FTP server, your FTP client has to support and be configured to use passive FTP.

Because the FTP authentication and data-transfer process is all in cleartext or unencrypted data packets, a new protocol has been created — Secure Copy Protocol (SCP) — which transfers files over ssh (covered later in this chapter) on TCP port 22. SCP has been replaced for most people with Secure File Transfer Protocol (SFTP), which also uses ssh and is a more feature-rich protocol.

Command shells

A shell is an interface for users to connect to. When you log onto your Windows computer, your desktop environment is generated by explorer.exe. On Unix and Linux servers, if administrators choose not to load a graphical environment, the shell application would be command line driven, usually with some variant of bash (Bourne-Again Shell). Because most Unix or Linux server administration can be done from the command line, remote shell access to a server is very important, both from the aspect of remote administration and for security. In addition to these servers, many network devices (such as routers, switches, and hardware firewalls) support a remote management command shell. The two most common methods of connecting to these command shells are telnet and ssh.

Windows Server 2008 has an installation method called Server Core Installation that does not install the default GUI (explorer.exe) but rather allows all administration to be performed via a command prompt or using GUI tools remotely. This type of installation reduces maintenance, the attack surface, and management, and also uses less disk space.

telnet

telnet, developed in 1969, has been the long-standing standard for remote management, in spite of its long-standing security flaw. The largest single flaw with telnet is that the entire communication process between the client and server takes place in cleartext. For any person in a position to view the raw network traffic, the entire conversation can be viewed, including the logon usernames and passwords. Server administrators moved to newer management technology some time ago, but many hardware manufacturers kept using telnet until fairly recently. Windows includes a default command line telnet application, and you can also get third-party graphical telnet applications that allow you to easily manage multiple sessions or capture log files of sessions.

ssh

ssh, developed in 1995, is short for secure shell. Remote access to a shell on a computer is what ssh is designed to secure, just like the name suggests. In addition to allowing remote shell access to servers, ssh allows for opening secure tunnels, allowing secure access to other systems on a remote network through the tunnel. When working with ssh with the lowest security level, the server uses a certificate to generate initial encryption keys and then encrypt the data stream between the client and server. For stronger security, client certificates can be used for authentication of the client as well as the server using its certificate. Server administrators that dealt with telnet cleartext data for years quickly converted to ssh when it became available, making it the new standard in remote shell access. Some telnet holdouts, like network switch manufacturers, have finally listened to their customers and added support for ssh. It is now prevalent on all systems that traditionally supported telnet. In order to use ssh, you will require a client, such as PuTTY (www.chiark.greenend.org.uk/~sgtatham/putty).

ssh should be considered the minimum connection mechanism for remote devices. telnet, with its cleartext data transfers, should no longer be considered.

Installing and Configuring Browsers

Internet Explorer (IE) is the default web browser for most Windows computers, partly because it comes installed with that OS. With this boost, Microsoft won the browser wars of the 1990s, which saw the main battle between IE and Netscape Navigator (even though both owed their roots to NCSA Mosaic). Although many different browsers were available in the beginning, these two products quickly rose to the top of the pile and battled it out. Today, there are different players in the game and there are a number of other browsers that can be downloaded and installed onto your system, such as Firefox, Opera, and Google Chrome.

The browsers today are fairly comparable and have similar features, such as pop-up blockers and tabbed browsing, plus the ability to choose from thousands of add-ons (extensions) written to enhance the web browser.

The following sections look at Internet Explorer, although similar settings are available in most web browsers.

To configure IE settings, open IE and choose Tools (the gear icon in the top-right corner) ⇒ Internet Options, which opens the Internet Options dialog box shown in Figure 4-7. This dialog box contains seven tabs, and I discuss each in the following sections.

FIGURE 4-7: Manage web browser settings through Internet Options.

Configuring General settings

From the General tab (shown in Figure 4-7), you configure settings for your home page, browsing history (including temporary Internet files), search defaults, and tabbed browsing. The other settings are primarily cosmetic. The settings for temporary Internet files allow you to choose the location of the files, how much space they will take on your hard drive, and your setting for refreshing content from the website directly.

Configuring Security settings

From the Security tab, you set security settings for sites in one of four zones. Most sites that you visit will fall into the Internet Zone, and the Local Intranet, Trusted Sites, and Restricted Sites affect only sites that you specifically enter onto those lists. Each zone can have different security settings. And, for each zone, you can choose from one of five security levels or specify your own custom settings. The five built-in levels are High, Medium-High, Medium, Medium-Low, and Low, although for the Internet setting, you can choose from only the three highest settings.

Click the Custom Level button to see exactly what settings are enabled. The settings in the resultant dialog box, also shown in Figure 4-8, allow you to set IE to handle a variety of components that may be embedded in web pages. For example, you can have IE disable, enable, or prompt you when it encounters certain components on websites, such as .NET Framework–reliant components, ActiveX controls and plug-ins, downloads (for files and fonts), scripting (including ActiveX scripting and Java applets), user authentication (often done automatically in the background), and a slew of user interface options.

FIGURE 4-8: Security settings in Internet Explorer can make the browser much safer.

Configuring Privacy settings

The IE Privacy tab, which deals with cookies and pop-ups, works in a similar fashion to the Security tab. Here, you can configure settings for cookies on a per-site basis as well as configuring general settings by using either the slider for levels from Allow All Cookies to Block All Cookies (with four levels in between) or by clicking the Advanced button and then customizing your cookie settings.

Cookies — settings that are stored on your computer by your web browser. When you return to the web server later, these settings are sent back to a web server. Websites use cookies to track users, especially if the site uses a shopping cart–transaction system. Shopping carts allow you to browse a catalog, select items you want, and check out. This mechanism is not only used at shopping sites but also at download sites, where you can select multiple files and download them all in one action at the end of your visit.

In addition to shopping carts, many sites will store a unique ID in a cookie on your computer to track your return to the site. In some cases, the IDs are used to set user preference or to track unique visitors. Cookies are stored in text files on your system and generally use very little space. When visiting one website, you might see content that comes from another web server, which is the case with most of the banner ads that appear on websites. If this other web server attempts to have a cookie stored, it is called a third-party cookie. You might want to block third-party cookies or all cookies if you are concerned about having companies track your activity on their websites.

If you choose to block pop-ups, click the Settings button to configure settings as well as a list of sites that are allowed to use pop-ups.

Configuring Content settings

From the Content tab, you can enable the Content Advisor, which makes use of voluntary tags that web content developers can include on web pages. These tags rate the level of language, nudity, sex, and violence found on the page. With the Content Advisor enabled, you can block content that is above the customized configured level. The Certificates section allows you view and modify (import and export) SSL certificates that IE uses. The Personal Information section allows you to modify the AutoComplete settings that are used on forms you encounter on websites.

Configuring Connections settings

A proxy server acts as a middleman when you request information from the Internet, allowing network administrators to restrict access through the network firewall, as well as audit what websites network users are going to. If you need to use a proxy server to browse the Internet, you can use the proxy settings to configure your access to proxy servers.

Proxy settings, found on the Connections tab, can be configured for each of the dial-up settings individually or for your LAN connection. Both have similar settings, so I discuss the LAN settings, which you reach by clicking the LAN Settings button. The settings are shown in Figure 4-9 and include automatic proxy detection and configuration, which requires specific configuration settings on your network.

FIGURE 4-9: If you are using proxy settings, you might need to regularly enable or disable the settings.

In addition to this setting, you can manually configure a proxy server address and port for your particular network and use that same server for http, https, ftp, gopher, and socks. The socks setting allows you to proxy protocols other than the default ones that are listed. You might use socks to proxy IRC or POP3. As with most cases, you can also configure a list of servers that are exceptions to using the proxy server, which might be the case when you have servers on your internal network that you don’t want to use a proxy server for.

Configuring Programs settings

From the Programs tab, you can specify which programs to use for different types of Internet services, such as HTML editing, email, and newsgroups. In addition, you can configure and manage IE add-ons, which are third-party components loaded automatically by IE. The add-ons section is where you will find any additional programs and toolbars that may have been loaded on your system. Having many of these items can slow down your system, so you may want to go into the add-ons and remove additional toolbars and extensions.

Working with Advanced settings

The last tab in Internet Explorer’s Internet Options dialog box is the Advanced tab. It has a variety of settings you can modify (by enabling or disabling features and functions) how IE works. These settings are Accessibility, Browsing, HTTP 1.1, Java, Multimedia, Printing, and Security. See Figure 4-10.

FIGURE 4-10: Security Settings are just one of the types of Advanced Settings.

Using the Internet

When using the Internet, be aware where you are going when you click links on your web browser. This section looks at what makes up the parts of a URL (Uniform Resource Locator), the string of text that appears on the address line in IE. The standard URL has an access method, a server name, and the path to a file or directory on the server. A typical URL resembles the following:

http://www.gleneclarke.com/sample_files/default.htm

In this example, http: represents the access method, //www.gleneclarke.com represents the name of the server being contacted, /sample_files represents the directory being navigated to, and /default.htm represents the file being requested. All URLs follow the same basic structure, but if you leave out one part of it — such as the document name — you will be given the default document for that directory or server.

Access methods

Table 4-1 summarizes some of the access methods for resources on the Internet. These access methods can be specified from the command line or from within a web browser.

TABLE 4-1 Access Methods

Access Method	Description
http:	Used to access web content on servers
https:	Used to secure http: access, using SSL to provide authentication and encryption services https: requires a certificate to provide verification of the server’s identity
ftp:	Used to copy files to and from remote servers
mailto:	Activates the local email client to send a message to the address specified in the server portion of the URL

Domain names and websites

Every computer on the Internet has a unique IP address. This address enables a computer to find and establish communications sessions with any other computer — that is, as long as you know the IP address of the computer you want to connect to.

Every IP address is potentially a 12-digit number. Because every IP address could be a 12-digit number — and because most people cannot remember hundreds of 12-digit numbers — the domain name system (DNS) was established in 1984. With DNS, you specify a name, and the DNS resolver or client on your computer will look up the required address for you on a DNS server.

Because each server could never be able to hold the names of all the computers on the Internet, DNS servers split up the job. Each server is responsible for knowing only a small number of computers, but the servers know how to find other servers. Figure 4-11 illustrates how the DNS is structured. At the top of the structure is the root (.) domain, which knows about all the servers that manage the top-level domains (TLDs). TLDs include com (commercial), org (organization), mil (military), edu (education), gov (government), and net (network), as well as a two-letter domain for every country in the world, such as au (Australia), us (United States), uk (United Kingdom), and de (Germany). The servers at the top level know about the servers that are responsible for the next level down, and so on.

FIGURE 4-11: Overview of the domain name system.

Restrictions around top-level domains have become more relaxed. As such, the Internet Corporation for Assigned Names and Numbers (ICANN) has registered several new TLDs, such as travel (travel industry), name (personal names), museum (museums), mobi (mobile products and services), jobs (HR related), info (informative websites), and aero (air transportation and aerospace; maintained by Internet Assigned Numbers Authority [IANA]). There are also misused TLDs, such as ws (officially for the country of Western Samoa, but often used for personal websites) and tv (officially for the country of Tuvalu, but often used for television-related sites).

DNS is a global directory that allows friendly names to be resolved to IP addresses. Without this function being performed, you would have to know every server’s IP address.

Here’s how it all works in real life. Say you want to connect to a server with a DNS name of www.gleneclarke.com. Your DNS client checks against your local server to see whether it knows the IP address for that DNS name. Even if your server is not the owner of that DNS name, it may have looked it up before and have the information cached. If the information is not cached on the local server, your server forwards the request to one of the root-level servers, which directs it to the .com server, which directs it to the gleneclarke server, which then looks up the www record.

This system gives your browser the capability of finding any computer on the Internet with a name registered with DNS. Many people register their servers by the type of service that they offer, such as ftp.gleneclarke.com, smtp.gleneclarke.com, pop3.gleneclarke.com, or mail.gleneclarke.com. HTTP allows you to place links on any server to any other server on the Internet, which allows you to have a very complex path configured to lead people through the Internet. Because this path is web-like, the interconnection of HTTP servers is referred to as the World Wide Web (www). www is the standard name that is given to the HTTP or web servers on the Internet.

When you connect to a server, the URL might have a path listed beyond the root directory, or it might have the complete path to a file on the server. If no filename is given, the web server usually displays a default document for that directory, such as default.htm or index.htm. If no default document exists for that directory and the server allows for viewing the directory listing, you will see a list of filenames found in the directory, with each filename being a link to the file. When no other condition is met, the server returns a not found or 404 error message.

Ways to Access the Internet

In addition to dial-up connections, many other types of connections can connect you to the Internet, and some of these connection types might be available in your area from local Internet service providers (ISPs). Some of these are used for home connections, and others are used primarily for connecting LANs to the Internet:

Dial-up
Cable
DSL
ISDN
T1/T3
Fiber
Satellite
Wireless
Line-of-sight wireless Internet service
Cellular (mobile hotspot)
WiMax

The following sections take a closer look at each of these Internet connection types.

Dial-up

Good-old reliable dial-up has remained a true friend of remote access and access to the Internet for years. For years, dial-up was the method available to most users, and dial-up access was much better than no access. Dial-up is still a standard way to connect to the Internet in many markets in which faster alternatives do not exist. The listed data rate for dial-up connections is 56 Kbps.

Cable

Cable connections implement a cable modem in your home or office that takes a digital network signal from your network card and translates (modulates) it into an analog broadband signal. This signal is then passed on to the cable network. Cable companies usually offer transmission speeds between 4 and 30 Mbps to their customers although actual speeds vary. This signal runs over existing cable, using previously unused signal areas of the medium. When using cable, you are on a shared medium with other users until your connection reaches the cable company’s office.

DSL

The most common form of Digital Subscriber Line (DSL) is Asynchronous Digital Subscriber Line (ADSL). An ADSL implementation works similarly to cable (see the preceding section) except that the device you have in your home or office takes the digital signal from your network card and passes it to a phone line. ADSL companies usually offer transmission speeds between 4 and 8 Mbps although actual speeds vary. Cable offers the same transmission speeds going to and from the Internet, but ADSL always has slower upload speeds because the connection is broken into upstream and downstream channels. With ASDL, surfing the Internet and copying large files from websites is very fast, but if you want to store a file on a website or send email with large attachments, your speeds will be substantially slower. Typical upload speeds for ADSL range between 64 Kbps and 1 Mbps.

The standards for ADSL2 and ADSL2+ have been released, so some vendors may choose to implement these versions of ADSL, allowing for download speeds from 5 to 12 Mbps for ADSL2 and up to 24 Mbps for ADSL2+, although both offer upload speeds only in the 1–3.5 Mbps range. With ADSL, you share the line only until you hit the Telco switching office, which typically must be closer than 3 miles (5 kilometers).

Broadband, high-speed Internet connections through cable, and DSL (of which ADSL is a subtype) have replaced dial-up in most regions.

ISDN

Integrated Services Digital Network (ISDN) service comes in two basic forms: basic rate and primary rate.

Basic-rate ISDN: Uses three channels: two 64 Kbps lines for data (128 Kbps) and one 16 Kbps line as a control channel, which is used for establishing and maintaining connections. The data channels are referred to as B channels, and the control channel is referred to as a D channel.
Primary-rate ISDN: Uses twenty-three 64 Kbps B data channels (1.44 Mbps) and one 64 Kbps D channel for control information.

T1/T3

T1 connections offer transmission speeds of 1.544 Mbps over 24 pairs of wires. Each pair of wires can carry a 64 Kbps signal, called a channel. T1 connections can be implemented over copper wire.

T3 connections, on the other hand, require a better medium than copper, such as microwave or fiber optic. They are capable of speeds ranging from 6 Mbps to 45 Mbps.

T1 and T3 are North American standards, and E1 and E3 are similar standards for the European community.

Fiber

Internet access over fiber connections is defined in the Optical Carrier (OC) standards. There are different levels of OC, with OC3 being a common type of Internet connection for large networks as it can carry voice, video, and other data at a transfer rate of 155.52 Mbps.

Internet service providers are now offering fiber to the home so that residential customers can get faster speeds than what are typically offered by DSL and cable connections. Fiber-to-the-home connections can have transfer rates of 150 Mbps!

Satellite

Satellite Internet services come in two basic flavors: one-way with terrestrial return and two-way. Because satellites providing service in most residential areas were designed to send data, the first Internet access over satellites involved downloading from the satellite, but data had to be uploaded via dial-up modem. This transmission tied up phone lines, and upload speeds were rather slow. Two-way systems added technology to return a signal to the satellite. Speeds for uploads ran in the neighborhood of only 1 Mbps, but they did free up phone lines. Download speeds over satellite systems rival those of broadband services (such as ADSL and cable). Just like satellite television, satellite Internet is susceptible to the weather and elements.

Wireless

Wireless access to the Internet is provided through standard 802.11 (WiFi) wireless networks, which are set up to provide coverage in prescribed areas. In some locations, wireless access is provided for free to customers of certain businesses, or by a municipal government like Fredericton, New Brunswick (www.fred-ezone.ca).

Sometimes, a company may set up access points in a wide range of locations, offering access through them as part of a subscription service. These wireless access points allow connectivity but only to the company’s website to set up an account. After you set up and pay for an account, you can use any of the company’s access points to access the Internet.

For more information about 802.11 networks, read Book 8, Chapter 2.

Line-of-sight wireless Internet service

A line-of-sight wireless connection is typically used by a company that wants to connect two locations that are spread over a distance to a network. To connect these two locations, the company will typically place large wireless antennas on top of the buildings to allow the antennas to have a clear line of sight between one another with nothing in between to obstruct the wireless signal.

Cellular and mobile hotspot

Sometimes called wireless, 3G, or 4G, this system makes use of a cellular provider’s wireless network (as opposed to 802.11 networking). To connect to a cellular network, you need a cellular modem for your computer or a cellular router for your network. The cellular modem may be built into your computer, or added as a PCMCIA card or a USB adapter; some phones may even be used as a cellular modem. The benefit of this technology is that you can access the Internet from anywhere your wireless provider has coverage. This is the same technology I cover in Book 8, Chapter 2 when discussing WAN cellular.

Speeds will vary with each wireless carrier, but you will see rated speeds anywhere from 384 Kbps up to 4.9 Mbps. Speeds are dependent upon the provider providing service on EDGE (Enhanced Data for GSM Evolution), High Data Rate (HDR), EV-DO (Evolution-Data Optimized, or Evolution-Data Only), or 3G (Third Generation) networks. 4G networks began emerging in 2010, driving data speeds to new levels.

Tethering

A common method of gaining Internet access on your computer or laptop is by using the Internet connection of your mobile phone. Tethering refers to using the Internet connection of your mobile phone by either physically connecting your phone to a laptop (or desktop) via a USB cable or via WiFi or Bluetooth. Once you connect the system to the phone, you are then able to use that phone’s Internet connection to browse the Internet.

Many mobile devices give you the capability to easily share your phone’s Internet connection. For example, to share the Internet connection off my iPhone, I can make the phone a WiFi hotspot so that a computer can connect to it like any other WiFi network. The steps to share your Internet connection on an iPhone are:

Log on to your iPhone and choose Settings.
Choose Personal Hotspot.
Enable Personal Hotspot and then set the password for the hotspot (shown in Figure 4-12).

FIGURE 4-12: Configuring a wireless hotspot on an iPhone.

Now that your mobile device has been enabled as a personal hotspot, you can connect to it from a wireless client and use the Internet connection of the phone to surf the Internet.

WiMax

WiMax is a wireless standard that stands for Worldwide Interoperability for Microwave Access. WiMax is a technology that is designed to cover wide areas like a cellular network, but provide the transfer rate of a wireless network!