Networking Quiz

Networking Fundamentals Study Guide

Internet

You know what it is :-p

Intranet

An internal, private network that uses the TCP/IP protocol to share resources within a home or organization network.

Extranet

A network connected to the internet that allows limited access to resources from the internet.

VPN

(Virtual Private Network) Allows authenticated users to connect to a network and access resources from a remote location.

Security Zones

The concept of dividing a network into separate zones based on security risks.

Firewalls

A firewall provides a layer of protection to devices on a network by blocking malicious people and code.

Perimeter Networks (DMZ)

A network that connects a intranet to the internet. It's generally placed on a subnet and uses firewalls and other security measures to protect the intranet while providing services like e-mail and internet access.

LAN

(Local Area Network) A network of connected devices limited to a single physical location.

LAN Addressing

All devices on a LAN are assigned an IP address. The IP address is divided into a network ID and a host ID. A subnet mask is used to determine which part of the IP address is the network ID and which is the host ID. The network ID identifies the subnet, and the host ID identifies the host. All devices connected to a network must have the same network ID and a unique host ID. A host ID of binary zero represents the network ID, and cannot be assigned to a host. A host ID of all binary ones represents the subnet broadcast ID, and cannot be assigned to a host. IP addresses can be assigned automatically using a DHCP server.

LAN Reserved Address Ranges

The following IP addresses are reserved for use on private networks:
10.0.0.1 to 10.255.255.254
172.16.01 to 172.31.255.254
192.168.1.1 to 192.168.255.254

VLANs

(Virtual Local Area Network) A VLAN uses a switch to divide the switch's ports into separate broadcast domains.

Leased Lines

A WAN link that is leased by an organization. Different WAN links include T1, T3, E1, E3, DSL, ISDN, P2P wireless bridge and ethernet WAN.

Dial-up

A WAN connection using phone lines. Speeds are slow. Maximum speed is 56 Kbps, but actual speeds are usually lower. Availability is good but reliability is poor, especially in bad weather.

ISDN

A set of communications standards for simultaneous digital transmission of voice, video, data, and other network services over telephone lines.

T1, T3, E1, E3

WAN links. Speeds are:
T1 - 1.5 Mbps
T3 - 44 Mbps
E1 - 2 Mbps
E3 - 34 Mbps
T1 and T3 are used in America while E1 and E3 are used in Europe.

DSL

(Digital Subscriber Line) A WAN connection phone lines. Data is transmitted digitally. Download speeds are 1 Mbps - 24 Mbps and uploading speeds are 3 Mbps. Availability is good.

Cable

A LAN connection using coaxial cable. The internet signal shares the same cable as the TV signals. Speeds can vary, but are generally fast. Typical download speed is 10 Mbps. Typical upload speed is 6 Mbps. Availability and reliability are generally good.

Wireless Standards

The most important wireless standards and their characteristics are:

Standard Speed Frequency (GHz) Distance (m) Notes
802.11a 54 Mbps 5 GHz 30
802.11b 11 Mbps 2.4 GHz 35 Can configure channels to avoid interference
802.11g 54 Mbps 2.4 GHz 35 Backward compatible with 802.11b
802.11n 300 Mbps 2.4 GHz or 5 GHz 70 Backward compatible with 802.11a, b and g

Wireless Security

The most important wireless security methods and their characteristics are:

Method Effectiveness Notes
WEP Cracked Only used as a last resort
WPA Cracked Only used as a last resort
WPA2 Good Very common
802.1x Very Good Requires an authentication server

Point-to-point Wireless

A wireless WAN link. Limited to line of sight connections. Maximum distance is about 25 miles.

Wireless bridging

A method of connecting networks with a wireless connection.

Switches

A network device that connects multiple devices in a subnet. A switch will forward broadcasts to all devices connected to it. transmission speeds are usually 10, 100, and 1000 Mbps. A typical switch will have 4 to 24 access ports. A uplink port is used to connect the switch to another switch or router. Most switches support the creation of VLANs. Ports can be configured to increase security by only allowing specific MAC addresses or disabling unused ports. A switch will separate collision domains. A managed switch can provide the ability to manage and monitor traffic on the network. Unmanaged switched are layer 2 devices, while managed switched are layer 3 devices (see OSI model).

Routers

A router is used to connect networks or subnets. Routers use a routing table to keep track of the networks they connect. All routers must have at least two ports. Routers do not forward broadcasts. In many networks, the router is also the default gateway. Static routes are routes that have been manually configured. Dynamic routes are configured automatically using the RIPv2 and OSPF protocols. A default route is a path that the router uses when another path isn't identified, usually the default gateway. Routers use a "metric" to decide the best way to route data. Routers use the NAT protocol to connect a LAN network with private addressing to a WAN. A computer running Windows Server with "Routing And Remote Access Service" can be configured as a router. Routers are layer 3 devices (see OSI model).

Physical Media

The most important physical media are:

Media Speed Max Length (m) Susceptibility Notes
UTP Cat 5 - 100 Mbps
Cat 5e - 1 Gbps
Cat 6 - 10 Gbps
100
100
55 to 100
Electrical noise
Cross talk
Interception
Very common
STP Same as UTP Same as UTP
Fiber Up to 10 Gbps Miles Expensive
Wireless Up to 300 Mbps Electrical noise
Interception
Cable (thinnet) 10 Mbps 185 No longer used

OSI model

An overview of the OSI model:

Protocols

Some common protocols and their ports are:

Port Protocol
20, 21 FTP
23 Telnet
25 SMTP
53 DNS
80 HTTP
110 POP3

IPv4

IPv4 a 32 bit binary addressing. It does not allow adequate addresses, so methods such as private addressing and NAT are used. IPv4 is being replaced by IPv6.

IPv6

IPv6 is a 128 bit hexadecimal addressing standard.

Names Resolution

Device and domain names can be resolved to IP addresses using DNS and WINS protocols.

Networking Services

An application running at the network application layer and above, that provides data storage, manipulation, presentation, communication or other capability which is often implemented using a client-server or peer-to-peer architecture based on application layer network protocols.

ping

Used to check connectivity with other devices.

tracert

Used to trace the route data takes through a network.

pingpath

Performs a tracert command with pings to determin data loss through the network.

Telnet

A command line interface that allows bidirectional communication with devices on a network.

ipconfig

Lists the computer's network configuration settings.

netstat

Used to check network statistics for the computer.

Protocols

Be familiar with the most common protocols used in networking.

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