Forming an IP Address

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Chapter 5

• Forming an IP Address

2
IPv4

• Version of IP used on the Internet today
• Classes A, B, and C are the only ones in use.
• Classes D and E are reserved for multicasting
  research.

3
IPv4 Subnetting

• Process of shifting the network part of an IP
  address into the node share
• Creates more logical network addresses with fewer
  hosts per network
• Makes it possible to subdivide network address so
  that it is a better match to the physical network
• Supernetting is the opposite

4
Classless InterDomain Routing (CIDR)

• Used in most networking equipment today
• Possible to use all ones and all zeros as subnet
  addresses
• Gives the ability to shift the boundary between
  network and host by a single bit and create two
  subnets as result

5
IPv6

• Designed to overcome limitations of IPv4
• 128 bit address length
• Divided into 8 16-bit sections which are
  converted into 4-digit hexadecimal numbers
  separated by colons
• Example 402A00002F7C000108BBFFE3728D095A
• Leading zeros can be left off 402A02F7C18BBF
  FE3728D95A

6
Default Gateways

• IP address of a router that is designated for any
  traffic for which the route is unknown
• On a computer connected to an internetwork, the
  default gateway is the IP address of a router on
  that computers segment.
• On a computer connected to the Internet through
  an ISP, the default gateway is the Internet
  Service Providers router IP address, which is
  used for all Internet-bound traffic

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Default Gateway
8
Default Gateway
9
Public and Private IP Networks

• A public IP network address is directly connected
  to the Internet.
• A private IP network address is used by networks
  that are either completely disconnected from the
  Internet or that use network address translation
  (NAT) to increase the number of IP addresses
  available on the internal network.

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Public and Private IP Networks

• Three private IP addresses are available, one for
  each class of IP address.
• The private class A network address is
  10.0.0.0/8.
• The private class B network address is
  172.16.0.0/12
• The private class C network address is
  192.168.0.0/16.
• Must be disconnected from the Internet or hidden
  behind a NAT or proxy server.

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Public and Private IP Networks

• NAT is used to translate IP addresses from one
  network and map them to a different IP address
  known within another network.
• The private IP address is used on the network
  that is designated as internal, and it is mapped
  to a public IP address used on the public
  Internet.

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TCP/IP Protocol Functions

• Application
• Application-layer services in the TCP/IP model
  encompass the application, presentation, and
  session layers in the OSI reference model.
• These protocols provide the primary data for a
  network administrator, and are the ones users
  will be most likely to interface with.

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Application LevelTCP/IP Protocol Functions

• Telnet
• FTP
• TFTP
• HTTP
• HTTPS
• POP3/IMAP4

• SMTP
• NTP
• SNMP

Pages 131-139
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Transport LevelTCP/IP Protocol Functions

• TCP
• UDP

Pages 139-140
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Network LevelTCP/IP Protocol Functions

• ARP
• ICMP (ping)
• IP

Pages 141-142
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Well-Known TCP and UDP Ports
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Naming and Addressing

• DHCP
• Dynamic Host Configuration Protocol provides IP
  addresses to network computers without an
  administrator manually assigning them.
• DHCP lets network administrators establish a
  central DHCP server and configure it to deliver
  IP addresses to DHCP clients.

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Naming and Addressing

• DNS
• The Domain Name System provides for a
  hierarchical naming system of computers on the
  Internet.
• Domain names are used to locate the DNS servers
  in a hierarchical fashion.
• A DNS server will forward a request to servers
  either directly above or below themselves in the
  hierarchy when they do not contain a listing for
  a particular domain name to IP address.

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DNS
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Naming and Addressing

• WINS
• Windows Internet Naming Service is used on
  networks that have NetBIOS names.
• Windows servers are placed on the network to
  maintain mappings of all IP addresses and NetBIOS
  names.
• WINS clients use a WINS server address to look up
  NetBIOS names.