Transcript Chapter 7 Part 2 Networks

Chapter 7 Part 2
Networks
• Why would I ever consider a wired network
connection over a wireless?
– Wireless signals are more susceptible to
interference from magnetic and electrical sources.
– Other wireless networks can interfere with the
signals on your network
– Certain building materials (concrete/cinder blocks,
metal) can decrease throughput.
– Distance from the networking equipment can
lessen throughput.
• How is data sent through a network?
– Network navigation devices facilitate and control the
flow of data through a network. Data is sent over
transmission media in bundles. Each bundle is called
a packet.
– Router – transfers packets of data between two or
more networks. (example: home network and the
internet would be 2 networks)
– Switch—a “traffic cop” receiving packets of data and
sending them where they are intended to go.
(Routers for home use have switches integrated into
them).
• Networking software
– What software do home networks require?
• Home networks need operating system software that
supports P2P networking. Windows, OS X, and Linux all
support P2P.
• You can connect computers running any of these OSs to
the same network.
– Is the same software used in client/server
networks?
• The centralized servers in a client/server
network have specialized network operating
systems (NOS). This software handles that
requests for information, internet access, and
the use of peripherals for the rest of the
nodes. Some examples of NOSs are Windows
Server 2008, R2, and SUSE Linux Enterprise
Server.
• Ethernets
– An Ethernet is a network named because it uses
the Ethernet Protocol as the means or standard by
which the nodes on the network communicate.
The Ethernet protocol was developed by the
Institute of Electrical and Electronics Engineers
(IEEE).
• Each standard that the IEEE develops is numbered with
802.11 being wireless, and 802.3 being wired.
• The 802.11 standard is also known as Wi-Fi.
– UTP-unsheilded twisted pair wire like cat5, cat5e,
and cat6 are often used for data transmission in a
network. Some precautions to take when running
UTP cable:
• Do not put sharp bends into the cable
• Avoid putting the cables in a location where there is
foot traffic.
• UTP cannot exceed 100 meters per run (328ft) or the
signal will degrade.
• Connecting devices to Routers
– How many devices can be connected to a router in
a home network?
• Most home wireless routers can support
up to 253 wireless connections at the
same time. This a theoretical maximum
(most home networks have fewer than 10
wireless devices)
• Network-Ready Devices
– A network-ready device is a device that can be
connected directly to the router, no need to
connect it to another computer on the network.
• Examples: Xbox 360, many DVRs
– A few devices still have network adapters, but
they are being phased out.
• Network Attached Storage device
– (NAS) a network attached storage device is a
specialized computing device used to store data.
They are popular with business networks. Think
of them as specialized external hard drives.
• Examples include MyBook from WD (Western
Digital). They connect directly to the router.
• For apple, Time Capsule operates as a wireless
router and NAS. (Airport is just a wireless
router for Apple.)
• Home Network Server
– This is a step up from a NAS, but it does not
turn a peer-to-peer network into a
client/server network because the functions
are more limited.
• Example: Acer Aspire Easy Store Server. It
connects as a node on the router and provides:
–Auto back up
–Shared file storage for the network
–Access gateway to the network
• Securing a Wireless Network
– All computers connected to the internet need
protection from intruders. This is usually
accomplished by a firewall. A firewall is either a piece
of hardware or software that acts as a shield to your
home network.
– Wireless network present added vulnerabilities. With
a wired network it is easy to tell if a hacker is using
your network (they would have to physically wire
themselves into it). A wireless network is invisible and
extends beyond the boundaries of a house or
apartment.
c.
Piggybacking-a term used to describe
illegally using a wireless connection.
• Why might a person be piggybacking?
– Accidental: most devices are set to use the
strongest signal available. In this case, a person may
be on the opposite side of their house from the WiFi
signal, and they can pick up their neighbor’s more
easily.
– Without permission: they can use your signal so
they do not have to pay for their own.
– For cyber attacks: if a person wishes to launch a
cyber attack, they do not want it traced back to
them. They will piggyback on your signal so that it
gets traced back to your IP address.
• Steps in securing your wireless network
– Change your network name (SSID). The default
Service Set Identifier is linked to default access codes
by the manufacturer. Changing your network name
will make it more difficult for hackers to find your
access code.
– Disable SSID broadcast. Most routers are set up to
broadcast their SSIDs so they are “discoverable” or
other devices can find them. (This would be good
protection from the accidental piggybacking.
– Change the default password
– Turn on security protocols. (WEP) wired
equivalent privacy or (WPA) Wi-Fi Protected
Access. These encrypt data sent into code. You
will need to set up a passphrase to allow
decryption.
– Implement (MAC) Media Access Control. There is
a serial number associated with network adapters.
You can specify which of these “addresses” are
allowed access to your network.
– Limit signal range. You can adjust the range at
which you broad cast the wireless signal. Settings
are low, medium, high.
– Apply firmware updates. As bugs are discovered,
hackers may try to exploit these vulnerabilities so
patches are made in the form of an update that
fixes the bug.
• How can I test the speed of my Internet
connection?
– Your ISP may have promised certain uploading and
downloading speeds. You can check the actual
throughput using some online applications.
• Speedtest.net and broadband.gov can test the
actual speed and they allow you to compare it
to others in your area or all over the US.