Technology

Technology

What does broadband mean?

The technology “Broadband” in general is used to refer to high-speed network connections. Connections to the Internet via cable modem and Digital Subscriber Line (DSL) are referred to as broadband Internet connections. The “Bandwidth” technology is the term used to describe the available speed of a network connection. As an example, most modern dial-up modems can support a bandwidth of 56 kbps (thousand bits per second). The bandwidth for a “broadband” connection, normally not defined, can exceed 1 Megabit per second (Mbps) or more.

What is cable modem access?

Cable modem technology will allow a single computer (or network of computers) to connect to the Internet via your local cable TV provider. The cable modem connects to your computer by either a USB (universal serial bus) or an Ethernet LAN (Local Area Network) connection. and is capable of speeds in excess of 5 Mbps.

Actual connection speeds will be lower than the maximum because cable connections are shared with neighbors also using cable modem connections and everyone shares the same bandwidth. Because of this cable modem users may experience somewhat slower internet access during periods of peak demand.

What is DSL access?

The technology of Digital Subscriber Line (DSL) Internet access, unlike cable modem internet access, provides you with dedicated bandwidth (you don’t share with your neighbors). The downside is that the maximum bandwidth available to DSL users is usually lower than the maximum cable modem rate because of the differences in each of the technologies. Additionally the “bandwidth” is only dedicated between your connection and the DSL provider — there is no guarantee of bandwidth speed on the Internet.

How are broadband services different from traditional dial-up services?

The old technology of Dial-up Internet services are “dial-on-demand” services. Your computer only connects to the Internet when it has something to send, such as email or a request to load a web page. Once the data is sent, or after a certain amount of idle time, the computer disconnects the call. Each call connects to a pool of modems at the ISP (internet service provider), and since your computers IP address is dynamically assigned, your computer is assigned a different IP address on each call. This makes it more difficult for an intruder to connect and take control of your computer.

Broadband services are referred to as “always-on” services because you don’t have to make a call when you want to connect to the Internet. The computer is always on the network when turned on and sends data through its network interface card (NIC). Since the connection is always up, your computer’s IP address will change less frequently (if at all), thus making it more of a fixed target for attack.

Many broadband service providers use well-known IP addresses for home users. So while an intruder will likely not know your specific computer belongs to you, they could know that your internet providers’ broadband customers are within a certain address range and this makes your computer a more likely target.

How is broadband access different from the network I use at work?

Corporate and government networks are typically protected by many layers of security, ranging from network firewalls to encryption. In addition, they usually have support staff who maintains the security and availability of these network connections.

Although your ISP (internet service provider) is responsible for maintaining the services they provide to you, you are ultimately responsible for your own computers. As a result, you should take reasonable precautions to secure your computers from accidental or intentional misuse. NOT-A-GEEK can help you with that.

What is a protocol?

A protocol is a well-defined specification that allows computers to communicate across a network. In a way, protocols define the “language” that computers can use to “talk” to each other.

What is IP?

IP stands for “Internet Protocol”. It is the common language of computers on the Internet. It is important to know a few things about IP to better understand how computers are secured.

What is an IP address?

IP addresses are analogous to telephone numbers – when you want to call someone on the telephone, you must first know their telephone number. Similarly, when a computer on the Internet needs to send data to another computer, it must first know its IP address. IP addresses are typically shown as four numbers separated by decimal points, or “dots”. For example, 10.24.254.3 and 192.168.62.231 are IP addresses.

If you need to make a telephone call but you only know the person’s name, you can look them up in the telephone directory (or call directory services) to get their telephone number. On the Internet, that directory is called the Domain Name System, or DNS for short. If you know the name of a server, say www.not-a-geek.com,

you type this into your web browser; your computer will then go ask its DNS server what the numeric IP address is that is associated with that name.

Every computer on the Internet has an IP address associated with it that uniquely identifies it. However, that address may change over time, especially if the computer is:

  • dialing into an Internet Service Provider (ISP)
  • connected behind a network firewall
  • connected to a broadband service using dynamic IP addressing.

What is static and dynamic addressing?

Static IP addressing occurs when an ISP permanently assigns one or more IP addresses for each user. These addresses do not change over time. However, if a static address is assigned but not in use, it is effectively wasted. Since ISPs have a limited number of addresses allocated to them, they sometimes need to make more efficient use of their addresses.

Dynamic IP addressing allows the ISP to efficiently utilize their address space. Using dynamic IP addressing, the IP addresses of individual user computers may change over time. If a dynamic address is not in use, it can be automatically reassigned to another computer as needed.

What is NAT?

Network Address Translation (NAT) provides a way to hide the IP addresses of a private network from the Internet while still allowing computers on that network to access the Internet. NAT can be used in many different ways, but one method frequently used by home users is called “masquerading”.

Using NAT masquerading, one or more devices on a LAN can be made to appear as a single IP address to the outside Internet. This allows for multiple computers in a home network to use a single cable modem or DSL connection without requiring the ISP to provide more than one IP address to the user. Using this method, the ISP-assigned IP address can be either static or dynamic. Most network firewalls support NAT masquerading.

What are TCP and UDP Ports?

TCP (Transmission Control Protocol) and UDP (User Datagram Protocol) are both protocols that use IP. Whereas IP allows two computers to talk to each other across the Internet, TCP and UDP allow individual applications (also known as “services”) on those computers to talk to each other.

In the same way that a telephone number or physical mail box might be associated with more than one person, a computer might have multiple applications (e.g. email, file services, web services) running on the same IP address. Ports allow a computer to differentiate services such as email data from web data. A port is simply a number associated with each application that uniquely identifies that service on that computer. Both TCP and UDP use ports to identify services. Some common port numbers are 80 for web (HTTP), 25 for email (SMTP), and 53 for Domain Name System (DNS).

What is a firewall?

A system or group of systems that enforces an access control policy between two networks. In a home network, a firewall typically takes one of two forms:

  • Software firewall – specialized software running on an individual computer, or
  • Network firewall – a dedicated device designed to protect one or more computers.

Both types of firewall allow the user to define access policies for inbound connections to the computers they are protecting. Many also provide the ability to control what services (ports) the protected computers are able to access on the Internet (outbound access). Most firewalls intended for home use come with pre-configured security policies from which the user chooses, and some allow the user to customize these policies for their specific needs.

What does antivirus software do?

There are a variety of antivirus software packages that operate in many different ways. Commonly, they all look for patterns in the files or memory of your computer that indicate the possible presence of a known virus. Antivirus packages know what to look for through the use of virus profiles (sometimes called “signatures”) provided by the vendor.

New viruses are discovered daily. The effectiveness of antivirus software is dependent on having the latest virus profiles installed on your computer so that it can look for recently discovered viruses. It is important to keep these profiles up to date.