The MicroTrain Blog

TCP/IP is today's most popular network protocol and is the protocol in the Internet. It is a routable protocol that provides connection between heterogeneous systems, these are the main reasons the protocol is so widely adapted; for example it allows communication between UNIX, Windows, Netware and Mac OS computers spread over multiple interconnected networks. The "TCP/IP protocol" is actually the "TCP/IP suite" composed of many different protocols each with its own functions. The two main protocols are in its name: the Internet Protocol and the Transmission Control Protocol.

IP addressing is assigning a 32-bit logical numeric address to a network device. Every IP address on the network must be unique. An IP address is represented in a dotted decimal format, for example: 159.101.6.8. As you can see the address is divided in 4 parts, these parts are called octets. The current used addressing schema in version 4 of IP is divided in 5 Classes:

TCP/IP Chart

A subnet mask is used to determine which part is the network part and which is the host part.
Default subnet masks

Class A     255.0.0.0
Class B     255.255.0.0
Class C     255.255.255.0

In a class A network, the first octet defines the network portion of the address. The last three octets are used for host addresses and subnet masking.

Network.Host.Host.Host
255.0.0.0

In a class B network, the first two octets define the network portion of the address. The last two octets are used for host addresses and subnet masking.

Network.Network.Host.Host
255.255.0.0

In a class C network, the first three octets define the network portion of the address. The last octet is used for host addresses and subnet masking.

Network.Network.Network.Host
255.255.255.0

A private network is one that will not be connecting directly to the Internet.  The term intranet is commonly use for this type of network.

The Internet Assigned Numbers Authority (IANA) has set aside the following IP address range for Intranet networks.

Private IP Address
IANA reserved 4 address ranges to be used in private networks; these addresses won't appear on the Internet avoiding IP address conflicts

10.0.0.0 through 10.255.255.255
172.16.0.0 through 172.31.255.255
192.168.0.0 through 192.168.255.255 

Special Addresses
Loopback Address                                127.0.0.1 (use for loopback test)

Destination                            Network                  Host

Host on this network              All zeroes               Host ID
Local Broadcast                    All ones                  All ones
Directed Broadcast                Network ID             All ones
Loopback Address                 127                       Anything

Automatic Private IP Addressing

(APIPA) is a feature of Windows-based operating systems that enables a computer to automatically assign itself an IP address when there is no Dynamic Host Configuration Protocol (DHCP) server available to perform that function. APIPA serves as a DHCP server failover mechanism and makes it easier to configure and support small local area networks (LANs).

169.254.0.0 - 169.254.255.255

If you have any questions please e-mail me at jescotal@microtrain.net

What is computer security?

Computer security is the process of preventing and detecting unauthorized use of your computer. Prevention measures help you to stop unauthorized users from accessing any part of your computer. By being proactive you can find out who is trying to break in to your computer system.

 Why should I care?

We use computers for everything from online banking, credit card transactions and communicating with others through email or social networking sites such as Facebook and Twitter. Although you may not consider your information to be "top secret," you probably do not want strangers reading your email, using your computer to attack other systems, sending forged email from your computer, or examining personal information stored on your computer (such as financial statements).

Who would want to break into my computer at home?

Hackers, Crackers and People who have nothing better to do with their time than to cause havoc.  Often they want to gain control of your computer so they can use it to launch attacks on other computer systems.

How easy is it to break into my computer?

Very easy many crackers find holes and vulnerabilities to exploit your computer.

Computer security risks to home users

What is at risk?

Information security is concerned with three main areas also known as CIA:

Confidentiality - information should be available only to those who rightfully have access to it

Integrity -- information should be modified only by those who are authorized to do so

Availability -- information should be accessible to those who need it when they need it

Here are some common risks associated with your computers?

The most common methods used by intruders to gain control of home computers are briefly described below.

Trojan Horse
Back Door Attack

Denial Of Service Attack

Man-in-the-Middle Attack
Unprotected Windows Shares

Keyloggers
Email Spoofing and Vulnerabilities
Virus

Spyware, Malware, Adware

Hidden File Extensions

Packet Sniffing

Social Engineering (Phishing)

Physical Theft (believe or not there are people that still do it the old fashion way)

Computer Security Protection

We recommends the following practices to home users in securing their computer and networks.

Firewall

Education, Awareness and Training

Service Packs, Hotfix and Security Patches

Antivirus Program
Antispyware Program

Do not open Email from unknown origins

Do not run any programs from unknown origins

Do not open unknown file attachment from unknown origins

Disable hidden filename extensions

Turn off your computer and disconnect network when not in use

Disable Java, JavaScript and Active X when possible

Backup

Make a boot disk or ghost an image of data in case of a disaster

Physical Protection

Lock Doors
Cameras

Bright Lights
Man Trap
Biometrics
Encryption

Common Sense

I hope this helps if you have any question contact me Jo Escotal at jescotal@microtrain.net