Module 12-15

Proper Netiquette

Be pleasant and polite Open with an appropriate greeting Check grammar and spelling Remember you are dealing with people Follow the standards of behavior that you follow in the rest of your life Know where you are in cyberspace Respect other's time and bandwidth

How many Internet users are there globally?

About 40% of the world's population is online...and growing.

Components and Structure of a WLAN

Access Points control access between a wired and a wireless network A wireless bridge connect two networks with a wireless link Wireless clients are commonly referred to as a STA or Station

Wireless LAN (WLAN)

Advantages: Mobility = easy connection of both stationary and mobile clients Scalability = ease of adding additional devices Flexibility = anytime, anywhere connectivity Cost Savings = inexpensive to install Reliability = easy to install

Network Number and Broadcast Address

All 0's in the host address is the Network Number All 1's in the host address in the Broadcast Address These two addresses can never be used when assigning IP's When finding the number of useable host addresses, you will always subtract 2 (network & Broadcast)

Wireless LAN Standards

Allow users to connect wireless hosts to other hosts or services on a wired Ethernet network

Subneting

Always remember that there are two reserved/unusable subnets Each time you borrow another bit from the host field, the number of subnets created increases by a power of 2 (doubles) Examples: Borrowing 2 bits creates four possible subnets 22 (2x2) Eight possible subnets are created by borrowing 3 bits: 23 (2 x 2 x 2) Sixteen possible subnets are created by borrowing 4 bits: 24 (2 x 2 x 2 x 2) What if you borrow one bit?

Converting to Binary

An IP Address is made up of 32 bits broken down into 4 Octets (8 bits each). 11000000.00001100.00000101.10101010or192.12.5.170 Known as the Dotted Decimal

Authentication

Authentication methods: Open does not require a secret word Used on APs by default Extensible Authentication Protocol (EAP) require an encrypted secret word Uses two-way authentication Pre-shared keys (PSK) require an encrypted secret word Uses one-way authentication

IPv6 & DNS

"A" record is used for IPv4 New "AAAA" record introduced for IPv6 Not all ISP support it yet

Global Unicast

A global-unicast IPv6 address starts with binary 001 or 2000::/3 through 2003::/3 Assigned to a single interface

IPv6 - IPv4 Addresses

A hybrid format may be used First 5 groups are IPv6, ffff, IPv4 dotted decimal notation Generic IPv6-IPv4 format: x:x:x:x:x:ffff:d.d.d.d Example of an IPv4 mapped IPv6 address with an IPv4 number on 192.168.0.5: 0.0.0.0.0.ffff.192.168.0.5 or ::ffff:192.168.0.5

Internet Protocol address (IP address)

A numerical label assigned to each device participating in a network Every device on the Internet must have a unique IP address to identify itself Internet Assigned Numbers Authority (IANA) Manages the IP address space allocations globally Delegates five regional Internet registries (RIRs) to allocate IP address blocks to local Internet registries (Internet service providers) For an IP to be routable over the Internet, it must have: IP address Subnet Mask Default Gateway DNS address (only for address lookup, i.e. web sites)

Planning the WLAN

A site survey - process of evaluating a network solution to deliver the required coverage, data rates, network capacity, roaming capacity, and quality of service Factors that affect the number of access points needed: The size of the building The number of solid interior walls in the building The present high voltage equipment (i.e. microwave ovens) Existing implementations Bandwidth requirements Total Cost of Ownership (TCO)

Why Subnet

A way of breaking networks into smaller more manageable pieces More efficiently use IP addresses Reduces the amount of wasted space Reduce the size of a broadcast domains Better bandwidth utilization

Chain of Custody

Chain of custody is important in preserving digital evidence of criminal activity during an investigation Note the date and time Document Report

Components and Structure of a WLAN

Channels are created by dividing up the available RF spectrum Each channel is capable of carrying a different conversation Uses an access method called Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) Creates a reservation on the channel While a reservation is in place, no other device may transmit on the channel

Fire Extinguisher Ratings

Class A - Ordinary materials (burning paper, lumber, cardboard, plastics) Class B - Flammable and combustible liquids (gasoline, kerosene, solvents) Class C- Electrical equipment (appliances, switches, panel boxes, power tools, and computers) Class D- Combustible metals (magnesium, titanium, potassium, and sodium) Most general use fire extinguishers are rated "ABC".

Accessibility

Computer accessibility - Accessible to all people, regardless of disability or severity of impairment Enabled through the operating system Also known as Assistive Technology Dexterity Impairments: Sticky keys allows characters or commands to be typed without having to hold down a modifier key (Shift, Ctrl, Alt) while pressing a second key Visual Impairment Use large fonts, high DPI displays, high-contrast themes, auditory feedback, screen magnifying software, or a braille display Hearing Impairment System sounds used with visual notifications and closed captions

Classful vs Classless

Divided into 5 classes A, B, C, D (multicast) and E (reserved) Does not send subnet information All networks are the same size Have the same subnet mask. Can NOT use first or last subnets

Safety Rules

Do not remove or install components while the computer is on or plugged in No food or drinks in the work area Remove all jewelry and watches. Keep the work area clean and orderly Keep computer disks away from magnetic fields, heat, and cold

Safety Rules

Do not touch any computer components with a magnetic screwdriver Do not use a pencil or metal tipped instrument to change DIP switches, jumpers, or touch components Cover sharp edges with tape when working inside the computer case Check all plugs and cords for wear damage prior to use

Broadcast Address

End with binary 1s in host bits Used to send data to all devices on a network Never used as a device IP address Example IP address: 152.21.2.3 Class B address First two octets are assigned Last two octets are host numbers used for devices in the network Broadcast address: 152.21.255.255

Network Address

Ends with binary 0s in all host bits Also know as the wire address Never used as a device IP address Used by routers to forward data Example IP address: 152.21.2.3 Class B First two octets are assigned Last two octets are host numbers used for devices in the network Network address: 152.21.0.0

IPv6 Address Format

Examples of the same address: 2001:0db8:0000:0000:0008:8000:0000:417a 2001:db8:0:0:8:8000:0:417a 2001:db8::8:8000:0:417a 2001:db8:0:0:8:8000::417a All leading zeroes can be omitted :: can be used once to represent a string of zeroes

Safety Rules

Familiarize yourself with your lab and the people that share it Familiarize yourself with the exits and the routes to them Stay alert and on the lookout for any condition that might pose a health and/or safety threat Notify the administrator immediately when you find a safety hazard or concern Always turn off the computer before moving it

IPv6 Tunnels

Fast and easy to set up Not the best for security or performance Free IPv4-to-IPv6 Tunnels Gogo6.com Sixxs.net Tunnelbroker.com

Automatic Private IP Addressing (APIPA)

Feature of modern operating systems Automatically self-configures an IP address and subnet mask when a DHCP server isn't available IP address range: 169.254.0.1 through 169.254.255.254 Configures a default class B subnet mask of 255.255.0.0 Used until a DHCP becomes available APIPA cannot be routed over the Internet

Occupational Safety and Health Administration (OSHA)

Federal agency charged with the enforcement of safety and health legislation OSHA requirements for a safe work environment: Provide properly maintained tools and equipment Keep records of accident reports Display an OSHA poster in a prominent location

Class A Addresses

First octet only identifies the network When written in a binary format, the first (leftmost) bit of a Class A address is always 0 (zero) Class A IP address example: 124.95.44.15 Range from 1-126 in their first octet 127 is part of a class A range but has been reserved for loopback testing Zero (0) can't be used Remaining three octets can be used for the host portion of the address 224 or 16,777,216, possible IP addresses per class A network

Addressing schemes Flat: Hierarchical:

Flat: used by intranet works, by layer 2, mac address. Hierarchical: Used by internetworks, layer 3, and used by IP address

Material Safety Data Sheet (MSDS)

Form containing information about the properties of a particular substance Intended to provide workers and emergency personnel with procedures and emergency phone numbers for handling or working with that substance in a safe manner Included information: Physical data Hazard rating Toxicity Health effects First aid

What is a Subnet Mask

Formal name: extended network prefix Tells the network devices which part of an address is the network field and which part is the host field 32 bits long and 4 octets, just like an IP address Bits are always borrowed from the left most available bit Allow numbers: 255, 254, 248, 240, 224, 192, 128, 0 Step to determine the subnet mask: Express the subnetwork IP address in binary form Replace the network and subnet portion of the address with all 1s Replace the host portion of the address with all 0s Convert the binary expression back to dotted-decimal notation

Private Addresses

Found in each class Preserve IP addresses used on the Internet Not routable or usable on the Internet Added security Used by: Hosts that use Network Address Translation (NAT) Proxy server to connect to a public network Hosts that do not connect to the Internet at all

Communication and Troubleshooting

Good communication skills will always be in demand Technical knowledge increases your ability to quickly determine a problem and find a solution Establish a good rapport with the customer Handle customers with respect and prompt attention Help the customer focus on and communicate the problem Stay positive by focusing on what you can do to help Convey an interest in helping the customer

Control Protocols

IPv4 Control Protocols: ARP ICMP IGMP IPv6 Control Protocol: ICMPv6

IPv4 Addresses: 32 Bits

IPv4 address: 192.168.1.10 Four bytes or octets 32 bits Dotted Decimal system In Binary: 11000000.10101000.00000001.00001010 232 total addresses or about 4 billion

IPv6 Addresses: 128 Bits

IPv6 address 2001:05c0:1000:000b:0000:0000:0000:66fb Eight fields Each 16 bits long 4 hexadecimal characters per field Separated by a colon (:) 128 bits total 2128 total addresses: 340,282,366,920,938,463,463,374,607,431,768,211,456 340 undecillion, 282 decillion, 366 nonillion, 920 octillion, 938 septillion, 463 sextillion, 463 quintillion, 374 quadrillion, 607 trillion, 431 billion, 768 million, 211 thousand and 456

Main Address Types

IPv6 addresses can be: Unicast - One-to-One address Identifies a single interface Used by the Link-Local and global unicast addresses Multicast - One-to-Many address Identifies multiple interfaces Delivered to all interfaces that are identified by the address Always begins with FF (1111 1111) Cannot be used as source addresses

Methods of IPv6 Migration

Ignore IPv6: Stay on IPv4-only Gateways: Devices that convert IPv6 to IPv4 Tunnel: IPv6 over IPv4 Dual-Stack: IPv4 and IPv6 together Nirvana: IPv6-only

Preventing ESD Damage

It is your responsibility to ensure you don't cause damage to systems you are servicing. Create an ESD workstation or environment to reduce ESD damage by using: ESD wristband strap ESD tables or mats Increase humidity Anti-static bags

Handling the Angry Customer

Let the customer tell their problem without interruption (even if they are angry) Empathize with the customer Focus on completing the task in an expedited manner Apologize for wait time or inconvenience Avoid putting this customer on hold or transferring them Avoid talking at length about the cause of the problem Upon closure, document the situation and inform the manager

MAC Address and Traffic Filtering

MAC address filtering Uses the MAC address to identify which devices are allowed to connect to the wireless network Traffic filtering Allows a network administrator to block undesirable traffic from entering or leaving the wireless network

Interface Configurations

Manual configuration Autoconfiguration (EUI-64) DHCPv6 Pseudo-random interface ID Cryptographically generated ID

IPv6 Advantages

More efficient address space allocation End-to-end addressing: no NAT Routers do not calculate header checksum Multicasting instead of broadcasting Built-in security mechanisms Single control protocol (ICMPv6) Auto-configuration

IPv6 Address Format

Multiple zeros can be omitted entirely but only once in an address 2001:0000:0000:0000:0000:0000:0000:003f

Service Set Identifier (SSID)

Name that identifies a wireless network Case-sensitive, alpha-numeric string that is up to 32-characters Tells a wireless device to which WLAN it belongs All wireless devices on the same WLAN must have the same SSID Sent in the header of all frames transmitted over the WLAN

Safety Rules

Never open or work on a monitor or power supply (AMPS KILL) Never look into a laser beam found in computer related equipment Make sure that a fire extinguisher and first aid kit are available and you know where they are and how to use them Read safety labels on all equipment in the lab, including the fire extinguisher

ESDs Effects

Our bodies constantly generate and release static electricity Almost every time we touch something, we discharge some amount of static electricity The human body can feel an electrostatic discharge of 3000+ volts Less than 100 volts can damage or destroy the delicate circuitry found in computers ESD buildup is greatly reduced in a humid environment Best between 40% and 60%

External Power Problems

Potential problems: Line noise Spikes Surges Brownouts Blackouts Can lead to reliability issues in your computer

Uninterruptible Power Supply (UPS)

Provides a constant (uninterruptible) power stream When the power drops below a certain level or is disrupted completely, the UPS kicks in to provide power for a certain amount of time Can handle brownout conditions

Ethics and Legal Aspects

Respect the customer and their property including, their equipment and their data E-mails Phone lists Records or data on the computer Hard copies of files, information, or data left on desk Obtain customer's permission before accessing their account Do not divulge customer information Know how to make and receive phone calls

Electro-Static Discharge (ESD)

Results in rapid movement of electrons Builds up a charge within our bodies seeking an outlet When we make contact with another electrically conductive material, the electrons jump from our body to the other material Looks for a lower charged outlet Static electricity - The buildup of an electrical charge within an object, such as a person, that is discharged in the form of electricity

Types of UPS

Standby UPS Operates normally from its AC side When the power drops, it switches over to its battery backup side No power conditioning abilities In-line UPS Operates normally from its DC or battery backup side The AC side is only used in the event of a problem with the battery-powered circuits Never plug a laser printer or monitor into a conventional UPS

Types of Addressing

Static IP address Manually assigned to a device by an administrator Constant and does not change. Dynamic IP address Assigned to device each time it starts Requires less human intervention Less administration Uses Dynamic Host Configuration Protocol (DHCP) Enabled by default No user intervention

Subneting

Subnet addresses include: The Class A, Class B, or Class C network portion A subnet field A host field Subnet field and the host field are created from the original host portion Provides addressing flexibility To create a subnet address: Network administrator borrows bits from the original host portion Designates them as the subnet field (gives up control)

Port Numbers in Client-Server Conversations

The destination port number is used to determine which applications or protocol should be used to handle the incoming segment

Encryption

The encoding of wireless data to prevent intercepted data from being read by a hacker Encryption methods: (WEP) Wired Equivalency Protocol Uses key lengths of 64 and 128 bits (WPA) Wi-Fi Protected Access Uses encryption keys from 64 bits up to 256 bits Generates new dynamic keys each time a client establishes a connection with the AP Considered more secure than WEP because it is significantly more difficult to crack

Network & Host Numbers

The formulas are the default configuration for each class: N = Network Number Assigned by the American Registry for Internet Numbers (ARIN) Administrator has no control over this part of the address H = Host Number Assigned and controlled by the network administrator

Calculating Subnets and Hosts

The more subnets you create, the less hosts each subnet will have

IPv6 Address Format

The network and host portions on IPv4 are now called the network id and interface id. IPv6 addresses are case sensitive and should always written in lower case

Boolean Operations

The term "operations" in mathematics refers to rules that define how one number combines with other numbers Boolean operators binary numbers: AND is like multiplication OR is like addition NOT changes 1 to 0, and 0 to 1 In order to route a data packet, the router must first determine the destination network/subnet address by performing a logical AND using the destination host's IP address and the subnet mask Result will be the network/subnet address

Important Address Types

The type of an IPv6 address is identified by the high-order bits of the address. Interfaces normally have two addresses, or more

Classful Subnetting

Things you must always find out first before finding your IP's:Bits Borrowed Subnet Mask Number of subnets Numbers of hosts Increment

Holds and Transfers

Transferring a customer: Let the customer finish speaking Explain that you will to transfer their call, to whom, and why Tell them the number you are transferring them to Ask for their permission to do so Tell the new technician the details of the case Thank the customer Putting a customer on hold: Let the customer finish speaking Explain that you will put the customer on hold and why Ask for their permission to do so Explain how long they will be on hold and what you will be doing during that time

Wireless Modes

Two wireless modes: Ad-hoc Mode - created by connecting clients in a peer-to-peer network. Does not use an AP Independent Basic Service Set (IBSS) Infrastructure Mode - The AP controls all communications and ensures that all STAs have equal access to the medium Basic Service Set (BSS) - uses a single AP Extended Service Set (ESS) uses multiple APs, each being an separate BSS

Handling the Inexperienced Customer

Use a simple step-by-step process of instructions Speak in plain terms Avoid using industry jargon Avoid sounding condescending or belittling

Surge Suppressor or Protector

Used by most home users Surge suppressor Reduces power problems by absorbing spikes and surges Smoothing out line noise (Line conditioning) Not all surge suppressors include line conditioning. Features to consider: Clamping voltage Clamping speed Energy absorption Levels of protection

Wireless Technologies

Uses infrared light and radio frequency transmissions as its signally technologies

Level-two Technician Responsibilities

Usually more knowledgeable about technology May have been working for the company for a longer period of time Receives escalated work orders from level-one technicians Calls the customer back to ask any additional questions May use remote access software to access the customer's computer to diagnose the problem and possibly to resolve the issue

Wireless Topologies

WPAN - devices dedicated to a single host WLAN - used to extend the boundaries of the local wired network IEEE 802.11 standards WWAN - covers extremely large areas Technologies such as Code Division Multiple Access (CDMA) or Global System for Mobile Communication (GSM) Each uses a higher power output to increase its coverage

Class B Addresses

When written in a binary format, the first (leftmost) bit of a Class B address is always 10 (one and zero) Class B IP address example: 151.10.13.28 The first two octets identify the network number assigned by ARIN Range from 128 to 191 in their first octet Remaining two octets can be used for the host portion of the address 216 or 65,536, possible IP addresses per class B network

Class C Addresses

When written in a binary format, the first (leftmost) bit of a Class C address is always 110 (one, one and zero) Class C IP address example: 201.110.213.28 The first three octets identify the network number assigned by ARIN Range from 192 to 223 in their first octet Last octet can be used for the host portion of the address 28 or 256, possible IP addresses per class C network

IMPORTANT!!!

You must always borrow at least 2 bits and you must always leave at least 2 bits One for the network number and one for the broadcast

Link-Local Addresses

fe80::/10 prefix Same as IPv4 169.254.0.0/16 Automatically assigned to an interface Valid in the scope of the given link! Not to be routed! Used for auto-configuration Used for neighbor discovery