IP Networking, Web,

1
IP Networking, Web, Network Security 101

• Building Your Foundation

2
Overall Agenda

• Introduction
• Internet Web basics
• IP addressing
• Classes CIDR Blocks
• AS Numbers
• DHCP, BGP, NAT
• Network Security
• Encryption
• Firewalls

3
Internet Web Overview
4
The Internet Web Revolution Or Hype!!!

• Is it
• Tulip mania?
• Or is it
• A new revolution scaling of economies (not
  unlike the railroads in 1835)
• Going from local to national to global

5
Changing Business Environments

• Moving to a digital, information-based economy
• More complex faster-paced
• virtual offices, Internet time,
  coopetition, disintermediation
• Issues of primary concern to businesses
• Improve the supply chain - tighten integration
  with suppliers
• No matter their size - increases efficiency and
  barriers to competition
• Strengthen the demand chain - deepen
  relationships with customers and creating new
  distribution channels
• Accelerate time-to-market - extend geographic
  reach without bricks and mortar
• Focus on core competencies - reduce costs while
  increasing levels of service

6
Whats Driving All The Excitement

• Virtual Private Networks (VPN)
• Audio and video conferencing
• Business Applications
• Entertainment
• Collaboration
• Commerce
• E-mail
• Virtual marketing

7
Benefits to the Corporation

• Increase revenues
• Boost sales force productivity
• Reduce marketing expense and increase exposure
• Increase customer satisfaction, but reduce
  support costs
• Boost overall corporate productivity - everyone
  on-line

8
Internet Web Basics
9
The Internet Past and Present (Great ROI For 25M)

• 1969 - ARPANET networking research - the start of
  the Internet ( first Man on Moon, Nixon
  Inaugurated, Woodstock in NY and Sesame Street
  debuts)
• 1972 - E-mail( Nixon visits China, Dow hits
  1,000, Watergate Scandal unfolds, FedEx and Nike
  founded)
• 1973 - International connections Ethernet
  (Godfather II released,Foreman defeats Frazier,
  Agnew resigns, Ford is new VP, World Trade
  Center is opened, and Roe V Wade)
• 1983- All computers on Arpanet must use TCP/IP.
  (cell phones make first appearance in
  Chicago,Australia wins Americas Cup, Michael
  Jackson releases Thriller)
• 1984 DNS introduced (Mac PC introduced, Olympic
  games in L.A., Reagan reelected, McEnroe wins
  U.S.open and Wimbledon)
• 1986 - NSFNET created (Platoon is Best Picture,
  Chernobyl explodes, Ivan Boesky pleads guilty to
  insider trading)
• 1990 - Commercialization of the Internet( East
  and West Germany Unite, Dances with wolves wins
  best picture, Hubbell telescope placed in Orbit)
• 1992 - World Wide Web is introduced ( 1,000,000
  computers on Net. John Gotti Convicted, Euro
  Disney opens, Clinton elected, L.A. Riots).
• 1993-INTERNIC formed to register IP and Domain
  Names (Elvis stamps Debut, Trade center bombed,
  Schindlers list wins best picture, 51 day
  standoff in Waco)
• 1995-NSFNET turns internet over to private
  sector starts Internet II.. The revolution
  begins (Oklahoma City bombing, O.J. Bronco Chase,
  Dow hits 5,000. Dean Martin dies. Silence of the
  Lambs wins Oscar)
• Today, growing faster than any sector
• In two years Internet access audience greater
  than number of households with Televisions after
  40 years
• Future E-everything

10
ARPANet Circa 1977
11
How The Internet Works

• Data is passed from one network to another by
  ISPs
• Traffic is passed by peering (cross-connecting)
  the networks at defined locations - Internet
  Exchange Points (IXPs)
• IXP locations
• Network Access Points (NAPs)
• Original jump-on points from old NSFNet
• PB NAP - San Francisco Bay Area, Ameritech NAP -
  Chicago, Sprint NAP - New York City (Pensauken,
  NJ)
• Metropolitan Area Exchange (MAE)
• Developed by MFS
• MAE East - Washington D.C., MAE West - San
  Francisco Bay Area, MAE-LA, MAE-Dallas,
  MAE-Chicago
• Palo Alto Internet Exchange (PAIX) NASA
• Of the 7,000 plus ISPs just in North America,
  only a select handful are large enough to peer,
  the rest buy transit

12
Also, The Internet Is Packet Switched Not Circuit
Switched

• Circuit Switched Networks
• 23 or 24 simultaneous connections
• 56/64 kbps of bandwidth per connection, bandwidth
  reserved whether used or not
• Packet Switched Networks
• 200 simultaneous connections possible
• 7.7 kbps average per user, total bandwidth shared
  amongst n users
• So, a single T-1 with packet data handles 8x the
  users, costs far less than equivalent circuit
  switched facilities

Packet Switched
Circuit Switched
13
So, The Internet Is A Collection Of Large ISP
Infrastructures
UUNet
MCI
XO
Sprint
AOL
14
Public NAPs Are Located Around The
Country(Network Access Point)
15
This Peering Allows Customers Of ISP A To
Communicate With Customers Of ISP B
16
But Not All Is Right In Mayberry!!!

• Public Peering Locations Are Severely Congested
• NAPs - given to the private sector from the
  government
• So bad that NSF (National Science Foundation)
  officially cut ties to the Internet May 13th,
  1995
• Government since has developed Internet II
• Only select government agencies and research
  institutions may jump-on
• Not all IXPs are telco hardened data centers
• MAE-East is in an underground parking garage
• Supposedly, 70 of Internet traffic goes through
  MAE-East

17
To Solve The Problem, ISPs Privately Peer!
18
Private Peering Has To Be Mutually
Advantageous! (Both Parties Have Large Amounts Of
Data That Need To Be Transferred Between Each
Other)
19
ATT Asia
Qwest
UUnet
UUnet
AUCS
Teleglobe
AADS NAP
NYIIX
Sprint
Digex
Exodus
CW
IDC
PSI
Sprint
SwissCom
Above
Level3
New York New York
PAIX
San Francisco California
LINX
Exodus
London England
Chicago Illinois
KTHNOC
Teleglobe
Stockholm Sweden
UUnet
NASA AMES
Palo Alto California
AMS-IX
ATT
Amsterdam Holland
Netscape
MAE Frankfurt
Mountain View California
MAE West
Frankfurt Germany
BIG ISP.com
deCIX
AGIS
Santa Clara California
SFINX
PB NAP
MAE Paris
Paris France
PARIX
Exodus
CW
Sprint
ATT
San Jose California
Pennsauken New Jersey
Qwest
Sprint NAP
MAE ATM West
Dallas Texas
Ashburn Virginia
AOL
Level3
Washington DC
UUnet
MAE East
Los Angeles California
Exodus
MAE LA
AOL
MAE ATM Central
Level3
MAE ATM East
Teleglobe
PSI
Qwest
Sprint
Exodus
CW
LA PB NAP
Qwest
UUnet
LAIIX
PSI
Level3
20
Vixie
Singtel
Telstra
Genuity
Inter Acces
ConXioN
DRAnet
4200
Netcom
France Telecom
UOI
NAPnet
IBM.IL
Net NetCO
OAR
Scruz
KDD
Stanford
Verio
Genuity
Teleglobe
ESnet
Alpha Dot
_at_Home
Digex
OneCall
Verio
IGN
Global Center
NetRail
IIJ
IGN
DEC
Cerfnet
CRL
ATT
Argonne
CAIS
I1
CERN
ATT Disc
IconNet
MIX
GoodNet
ELI
N
IconNet
ELI
Quza
Epoch
IDT
CET
AADS NAP
UUnet
UUnet
ATT Asia
Qwest
AUCS
Teleglobe
NYIIX
Sprint
Digex
Global Center
Nuri
Exodus
FiberNet
ISBEnet
Road Runner
Exodus
PSI
Sprint
CW
IDC
SwissCom
Above
M
New York New York
Level3
San Francisco California
LINX
London England
Exodus
Chicago Illinois
CP
HK Tel
Above
Globix
NWU
PAIX
KTHNOC
Teleglobe
Stockholm Sweden
UUnet
NASA AMES
Data Place
Road Runner
Palo Alto California
AMS-IX
A
ATT
Amsterdam Holland
L
Netscape
TW
MAE Frankfurt
Mountain View California
B
BIG ISP.com
K
MAE West
Frankfurt Germany
J
deCIX
AGIS
Santa Clara California
SFINX
PB NAP
MAE Paris
C
I
Paris France
H
PARIX
Exodus
CW
Sprint
ATT
San Jose California
Pennsauken New Jersey
G
Qwest
Sprint NAP
HE.net
BBN
MAE ATM West
Dallas Texas
Ashburn Virginia
F
AOL
Washington DC
Level3
MAE East
UUnet
NetRail
Globix
MAE LA
Los Angeles California
Exodus
AOL
MAE ATM Central
Megs Inet
MAE ATM East
E
Level3
Teleglobe
PSI
Qwest
Sprint
_at_home
Road Runner
LA PB NAP
Exodus
CW
Qwest
Voicenet
Data Place
UUnet
LAIIX
PSI
Level3
Interpath
TW
D
Road Runner
ATT Disc
Above
Voicenet
BBN
Road Runner
Globix
TW
Oleane
Gridnet
_at_Home
Cable Inet
Globix
Erols
Global Center
Road Runner
CAIS
Digex
Above
Voicenet
ATT Disc
Global Center
KDD
IDT
IGN
DTAG
Genuity
Los Netos
IIJ
Epoch
ESnet
Digex
Cerfnet
Above
21
CRL
Netcom
Scruz
NAPnet
Lighting
Colt
EUnet
Net Access
LINX
LINX
LINX
LINX
LINX
LINX
LINX
LINX
IGN
ConXioN
EUnet
ICONnet
Wirehub
FiberNet
TTSG
LINX
LINX
LINX
LINX
LINX
LINX
LINX
LINX
Above
Planet Online
GoodNet
Well
Zocalo
LINX
LINX
LINX
LINX
LINX
LINX
LINX
LINX
ESnet
NASA
ATT Disc
DPnet
LINX
LINX
LINX
LINX
LINX
LINX
LINX
LINX
IDT
CERFnet
LINX
LINX
LINX
LINX
LINX
Digex
LINX
LINX
LINX
Erols
Linkage
LINX
LINX
LINX
ELI
LINX
dGIX
dGIX
dGIX
Brainstorm
Nacamar
Verio
dGIX
dGIX
dGIX
N
Data Exchange
CAIS
A
M
dGIX
dGIX
dGIX
BIG ISP.com
B
L
Verio
IDC
dGIX
dGIX
dGIX
C
K
D
J
dGIX
dGIX
dGIX
E
I
ATT
Compu Serve
F
dGIX
dGIX
H
dGIX
G
Netcom
MIBX
Net Konect
AIN
NetAsset
Well
PBI
ServInt
Surfnet
Support Net
InTouch
EUnet
DTAG
GoodNet
AGIS
Genuity
IIJ
OneCall
Getnet
Gridnet
IGN
Euronet
BBN
Erols
FiberNet
Verio
CRL
Data Exchange
_at_Home
NAPnet
NetRail
AGIS
Global Center
ConXioN
CERFnet
Wirehub
Telanor
UUnet NL
TEN
Nacamar
Teleglobe
FCI
Netnews
IGN
Interpath
EuroNet
CRL
Singtel
NetRail
MAI
Belnet
Sprint Intl
Eunet
Epoch
France Telecom
Cabletel
ELI
NASA
ConXioN
IDT
Erols
ConXion
Netcom
ESnet
Cistron
Digex
Above
Media ways
Genuity
ELI
WireHub
CAIS
A2000
Scruz
Vixie
INS
22
Smaller ISPs Must Rely On Severely Congested
Public Peering Locations, Or Transit From A
Larger ISP
NAP
NAP
ISP
23
AS NumbersAn ISPs Social Security Number
24
AS Numbers - Networks on the Internet

• Every network on the Internet has a unique
  identifier or AS number.
• AS Autonomous System
• Without an AS number you cannot tell the world
  about your content, you cannot announce your
  routes, you cannot have BGP
• Managed and controlled by ARIN
• XO is ASN 2828, XO Europe is ASN 5413
• ASN 5413 announces all of AS 2828
• UUNET is ASN 701
• Genuity (BBN) is ASN 1 (they were the first)
• etc...

25
Where ISPs are on the Internet.
26
Example of US Internet Peering Infrastructure
To Europe
27
Example Of European Internet Peering
Infrastructure
Stockholm
London
Public Peering
Public Peering
- KTHNOC
- LINX
Private Peering
To USA
Amsterdam
- Infonet Europe
Public Peering
- Abovenet
- AMS-IX
- Ebone
Paris
Frankfurt
Public Peering
Public Peering
- PARIX
- deCIX
- SFINX
28
So, You Want To Be An ISP

• You will need
• An AS Number (BGP requires it)
• Without you cant be identified
• Get it from ARIN
• Public/Private peering or transit relationships
• Almost impossible to get peering now days
  (usually done through acquisition)
• DNS, email, web servers, etc.
• IP address blocks from ARIN
• 24x7 technical support staff
• Solid infrastructure of routers, switches,
  servers, etc.
• And last.LOTS OF MONEY

29
The Internet Is Truly A Network Of Networks
30
Some Of The Nuts Bolts
31
OSI vs. TCP/IP

• Both have been around since the 70s

OSI
TCP/IP
Application (Layer 7)
Application
Presentation (Layer 6)
Session (Layer 5)
Transport (Layer 4)
Transmission Control
Network (Layer 3)
Internet
Data Link (Layer 2)
Subnet
Physical (Layer 1)
32
What Is TCP/IP??

• IP connectionless protocol
• Responsible for the sending/routing of IP
  Datagrams
• Analogy sending a letter
• TCP connection-oriented protocol
• Responsible for reliable transport of IP
  Datagrams
• Analogy placing a phone call

33
The IP Protocol

• Performs packetization of user data
• IP is the hatchet man of the protocol stack- it
  segments and packets data in Datagrams, but IP
  has not intelligence
• Puts header on datagram and shoots it out.
• Datagrams can take various paths/ no assurance of
  arrival or arriving uncorrupted
• Allows nodes to read header and route to next
  downstream connection. If anything on Network
  path gets corrupted the Datagram is discarded.No
  return message saying Datagram did not arrive .
  This simplicity improves Network efficiency

34
The TCP Protocol

• Transmission Control Protocol provides the brains
  to overcome IP
• At receiving end it puts data back into its
  proper sequence and ensures accuracy
• At sending end
• Puts a byte count header in the Datagram for
  comparison at receiving end. If Data is corrupted
  or does not arrive a message is sent back
  requesting the data again.

35
TCP Continued!

• TCP also holds all Datagrams (buffers them) until
  all lost packets are re-sent and able to be
  assembled in their proper order.
• This makes data reception and accuracy the
  responsibility of the end user and not the
  Network. TCP orchestrates the connection
• The network is only a transport system not a
  computer processing function

36
IP Addressing
37
Binary Math The Foundation of IP Addressing

• Computers use the binary numbering system
  (on/off)
• 1s and 0s or the power of 2
• Number of 1s/0s determines number of unique
  combinations
• The longer the string the more unique
  combinations
• But who can remember all those 1s and 0s, so
  heres an easy way to convert

153
38
IP Addressing

• An IP address is a software-based numeric
  identifier assigned to each machine on an IP
  network.
• Each Computer is distinguished by this unique IP
  address.
• Combination of 32 ones and zeros
• eg. 11100011.00010100.11111001.1010101 identifies
  one unique computer host

39
IP Addressing Continued

• Two methods of IP Addressing
• Class based
• An IP address is organized into 4 groups of 8bit
  numbers such as199.232.255.113
• Classless based
• An IP address is organized into one block of 32
  bits, counting right to left in decreasing order

--------

--------
40
IP Addresses

• IP addresses are made up of network and host
  addresses-
• in 199.232.255.113 the 199.232.255 is the Network
  address shared by every machine on that network.
  The .113 is the host address assigned to a
  particular machine.
• IP addresses are difficult to remember so domain
  names are mapped to each IP address

41
IP Addresses Can Be Broken Into Classes

• Class As, Bs, Cs, Ds, Es
• But only Class As through Cs have really been
  used.

42
Class A addresses

• Class A networks- the El grande of IP networks
• Only 126 class A addresses are possible. Each
  Class A network can have in excess of 16 million
  computers in its individual networks

43
Class B addresses

• Class B Networks- Can have 65,000 workstations on
  the network. There are approximately. 65,000
  Class B networks

44
Class C addresses

• Class C Networks- can have 254 workstations on
  the network. There are several million Class C
  Networks.

45
CIDR Blocks

• CIDR- Classless Internet Domain Routing.
• With a New Network being connected to internet
  every 30 minutes the Internet faced two problems
  Running out of IP addresses. Running out of
  capacity in the global routing tables
• Because Addresses were only assigned in three
  classes there was a lot of wasted addresses IE.
  If you needed 100 addresses you would be assigned
  a Class C. But that meant 154 addresses were
  unused. CIDR solutions- replaces old wasteful
  practice of assigning class BC addresses.
  ALLOWS FOR ARBITRARY SIZED NETWORKS

46
MORE CIDR

• An ISP can carve out a block of registered IP
  addresses to specifically meet the needs of each
  client
• CIDR allows a single routing table entry to
  specify how to route traffic to many individual
  network addresses. This route aggregation helps
  control the amount of routing information on the
  Internets backbone routers.

47
CIDR

• A CIDR address includes the standard 32-bit IP
  address and also information on how many bits are
  used for the network prefix.
• In the CIDR address 206.13.01.48/24, the "/24"
  indicates the first 24 bits are used to identify
  the unique network leaving the remaining 8 bits
  to identify the specific hosts or 256
• So if someone asks for a / 27 they are telling
  you in geek speak they need 25 or 32 IP addresses

5
48
IP Address Domain Name Registration

• Responsibility for management/distribution of IP
  addresses handled by 3 Regional Internet
  Registries (RIR)
• ARIN - American Registry for Internet Numbers
• RIPE - Reseaux IP Europeens
• APNIC - Asia Pacific Network Information Center
• ARIN requirements
• Must use 50 of IP address allocation immediately
• Must use 80 of IP address allocation within 6
  months
• Must use 100 of IP address allocation by year
  end
• If not, and ISP is audited, customer may have to
  turn-in all addresses

49
North America - Domain Names Are Registered With
Network Solutions (And Others)

• Used to be called InterNIC
• Cooperative effort between the U.S. Government
  and a private company, Network Solutions (Now
  Verisign) (www.networksolutions.com)
  (www.netsol.com)
• Currently, about 15 other companies compete with
  Network Solutions for domain name registration
• Management distribution of domain names
• Once the domain name is registered, Network
  Solutions propagates the name to all the domain
  name system (DNS) servers on the Internet

50
An IP Example!!!

• The Internet is divided into addressing Domains
• Within a domain detailed information is available
  about all networks that reside in that domain.
  Outside the domain, only the network prefix is
  advertised. This allows a single routing table
  entry to specify a route to many network addresses

200.25.46.0/20
200.25.0.0/16 one routing table for all these
networks and hosts
Internet
ISP
200.25.16.0/21
200.25.30.0/23
200.25.24.0/22
200.25.30.0/24 200.25.31.0/24
200.25.16.0/24 200.25.17.0/24 200.25.18.0/24 200.2
5.19.0/24 200.25.20.0/24
200.25.24.0/24 200.25.25.0/24 200.25.26.0/24
Organization A
Organization C
Organization B
51
How Do You Know How Many IP Addresses You Need?

• Three IPs are always non usable
• In, Out, and CPE (Network, Gateway, and
  Broadcast)
• How many hosts/computers/PCs, etc. does the
  customer have
• Does the customer own their own IP address block?
• What is the future growth of the customer?

52
But These Decimal Based IP Addresses Are Hard To
Remember!!!
53
Enter Domain Names!!!
54
Enter Domain Names?

• What is a Domain Name?
• A companys Internet Identity
• A companys online brand
• Something easy to remember
• Totally unique
• Addressing construct used for identifying
  locating computers on the Internet.
• www.xo.com 38.195.90.87
• xo.com Represents the Company XO Communications.
• When you type xo.com in a web browser or send
  e-mail to someone at xo.com, the Domain Name
  System (DNS) translates xo.com into the IP
  numbers used by the Internet.
• Resides on a computer called a the Domain Name
  Server

55
What is the Domain Name System?

• Method for computers to contact each other to
  exchange email and display Web pages using IP
  address information
• Distributed database used to translate domain
  names into IP addresses.
• Maintains specific portion of that global
  database for a company
• Specific company data held in each portion of the
  database and is made available to all computers
  and users on the Internet.
• Comprised of computers, data files, software, and
  people working together so interoperable
  communications are possible.

56
What are Domain Name Servers?

• Connected Internet with special software to
  translate Domain Names into numerical addresses
  or IP Addresses
• Two types of Domain Name Servers Local and
  Global
• Local Name Servers
• House all the names and IP addresses for your
  local network devices
• Maintain the local DNS database information
• Usually a Primary and Secondary Local Domain Name
  Server Exist
• Global Name Servers
• House the names and IP addresses for all of the
  Local Name Servers connected to the Internet.
• Public Registries (like Network Solutions, a.k.a.
  InterNIC) maintain the global DNS database
  information.

57
How the Domain Stuff Works.
1. You request IP address info for www.XO.com (an
A record)
2. The Local Name Server has no idea who
www.xo.com is.so the request is forwarded
to a Global Name Server
6. Your Web browser now uses the IP address
to contact the proper site
5. The info is forwarded back to the
Global Name Server
3. The Global Name Server knows of a Primary
Local Name Server that might know the
info and forwards..
4. The Primary Local Name Server didnt
know but the Secondary Local Name
Server did
58
How does e.mail work ?
1. Mail Server A requests IP address info for the
MX of xo.com
2. The Local Name Server has no idea what MX
address for xo.com is.so the request is
forwarded to a Global Name Server
Local Name Server
MX for xo.com
206.129.70.22
The Internet
Global Name Server
(Public Registry)
6. Mail Server A now uses the IP address
to forward the mail to Mail Server B
MX for xo.com
206.129.70.22
5. The info is forwarded back to the
Global Name Server
3. The Global Name Server knows of a Primary
Local Name Server that might know the
info and forwards..
4. The Primary Local Name Server didnt
know but the Secondary Local Name
Server did
Primary
Secondary
Local Name Server
Local Name Server
59
So what if more than one internet connection is
required?
60
You Need Border Gateway Protocol (BGP)!!!

• Border Gateway Protocol Addresses what path a
  packet will take to get to its destination
• BGP maintains routing tables that list all
  feasible paths to a particular network
• The Primary function of a BGP system is to
  exchange Network Reachability information,
  including information about the list of
  autonomous system paths, with other BGP
  systemsBGP is the way a system says I know how
  to deliver packets to this destination

61
BGP Continued

• So Who needs this stuff
• ISPs that have more than one peering point (US)
• A company that wants to be multihomed to
  different ISPs (Two connections Via different
  service providers)
• With One upstream provider you only have one path
  out of your network and you are on their CIDR
  block anyway.

62
Additional Internet Routing Stuff!!!
Routing Vs. Bridging
63
Whats the difference between bridging and
routing?
Bridging Basic access to the Internet. No IP
associated with the actual bridge. Think of a
Bridge like a piece of wire connected directly to
your workstation.
Routing More secure than a Bridge. Has a WAN and
LAN IP. Think of a Router like a box with side A
and B. Each side had an IP.
64
Bridging
No, but let me ask the guy thats next to me.
Naw, its not mine. Hey, you in the red tie, are
you John Doe?
65
Routing
I have a wallet for a John Doe at 555-1234.
Blah, blah, blah...
Blah, blah...
66
Network Address Translation (NAT)

• Uses a translation protocol to turn private, non
  Internet routable addresses into addresses that
  can be routed over the public Internet.
• Hides internal IP addresses to the Internet (a
  basic firewall)
• Can not Telenet/Can not host multiple servers of
  the same protocol

67

• NAT Continued
• Allows an organization to present itself to the
  internet with one IP address
• XO Customer Network private numbering allows
  LANs to utilize fewer public IP addresses.
• Standard Protocol - helps preserve unlimited use
  of IP addresses. Allows customer independence by
  being in control and managing their own internal
  IP addressing scheme.
• Enables a company to use as many internal IPs as
  needed without having to renumber machines if
  ISPs change

68
NAT in Action
Network Address Translation Hotel
69
Network Address Translation

• A list at the front desk of each client
  registered to what room.
• Configured client list within the router
• Customer is responsible for completing the
  configuration
• The bell boy checks the list
• Router reads the list
• Bell Boy delivers mail the to the correct room.
• Router delivers internet traffic to requested MAC
  address

70
Benefits of NAT

• Hotel Security
• Basic level of security on a private network
• Protects users anonymity
• Cheaper than purchasing IP addresses for each
  individual user

71
IP Addresses - Public and Non Public
Private Network
10.10.10.1 10.10.10.2 10.10.10.3 10.10.10.4 10.10.
10.5 10.10.10.6 10.10.10.253
Public IP Address
130.5.0.1
Internet
Router
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So, Define NAT
Network Address Translation An Internet standard
that enables a local area network (LAN) to use
one set of IP addresses for internal traffic and
a second set of addresses for external use.
How much does NAT cost?
NO ADDED COST!!!
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Dynamic Host Configuration Protocol (DHCP)

• What is it???
• Allows IP addressing information to be
  dynamically assigned by a server to clients on an
  as-needed basis.
• IP addresses are stored in a pool
• Allocated to computers on a network as they log
  on
• IP addresses are returned to the pool when the
  client or computer logs off
• Automatic assignment frees IT staff to deal with
  other pressing company needs

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CONFIGURATION OF DHCP

• In order to configure routers for DHCP the
  following information is necessary
• Does the customer want NAT also? Yes or no
• Does the customer want public or private
  addressing
• DHCP server IP address pool
• Customer Domain Name
• ISP will provide to the customer
• IP address of the DNS (Domain Name Service)
  Server
• IP address block (pool)

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DHCP Review
Define DHCP
Dynamic Host Configuration Protocol. DHCP is a
TCP/IP protocol that enables PCs and
workstations to get temporary or private IP
addresses from a pool in a centrally administered
server.
Name a benefit of DHCP
DHCP frees up time for customer IT employees in
order to take care of other company needs. Saves

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The World Wide Web
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World Wide Web Vast Collection of
Internet-Accessible Information (Web Sites)
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Web Browsers Enable Computers To Access The Web
view Web sites

• Web browsers reside on the users computer
• Based on the particular operating system used by
  the user
• MAC OS, Windows, NT, UNIX
• Major Web browsers
• Netscape Navigator
• Microsoft Internet Explorer
• AOL (which is based on Microsoft Internet
  Explorer)

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Web Sites Are Collections Of Individual Web Pages
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Web Site have Unique Addresses Called Domain
Names or URLs (Uniform Resource Locator)
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Each page within the Web site has its own unique
URL
http//www.corvettemike.com/red_corvette.html
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Each Web Page Consists Of An HTML File Related
Photo Graphic Files
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When Users Request A Web page - Web Server Copies
Sends the files
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Users Web Browser Reads The HTML File
Assembles The Page
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How Are Web Sites Built?
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Three Basic Methods Of Building A Web Site
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Regardless of the method used, all Web pages are
written in HTML (Hypertext Markup Language)
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Once complete, the Web site files are uploaded to
the Web Server.
1) The user can transfer the files from the PC
to the Web Server using the File Manager function
Upload File
/web
2) If the site is built with Microsoft
FrontPage, the user can use the Microsoft
FrontPage publish feature, which
transfers files to the Web server automatically
3) The user can also use FTP (File Transport
Protocol) software
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Advanced Web Site Features!
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SSL (Secure Socket Layer) Security
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CGI (Common Gateway Interface) scripts
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In Summary

• Internet is the infrastructure that WWW rides on
• It is truly ubiquitous
• It drives the cost of doing business down
• It levels the playing field for all companies
• It is NOT Hype, it is a revolution