Networking with TCPIP and the Internet

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Networking with TCP/IP and the Internet

• Dean (3rd), Chapter 11

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Objectives

• TCP/IP effect on network design
• Subnetting, CIDR, and NAT
• Mail protocols
• Voice over IP (VoIP)
• TCP/IP utilities for network discovery and
  troubleshooting

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TCP/IP-Based Subnetting

• Enhance security
• Improve performance
• Simplify troubleshooting
• Classful Addressing
• Subnet Masks

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Classful Addressing
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Special IPv4 Addresses

• this network 0.0.0.0 0.255.255.255
• Private networks
• 10.0.0.0 10.255.255.255
• 172.16.0.0 172.31.255.255
• 192.168.0.0 192.168.255.255
• Public data networks 14.0.0.0 14.255.255.255
• Cable operators 24.0.0.0 24.255.255.255
• Class A Subnet Experiment 39.0.0.0
  39.255.255.255
• Loop back 127.0.0.0 127.255.255.255
• Auto-configuration 169.254.0.0 169.254.255.255
• TEST-NET for example code 192.0.2.0
  192.0.2.255
• 6to4 relay anycast 192.88.99.0 192.88.99.255
• Benchmarking devices 198.18.0.0 198.19.255.255
• Multicast 224.0.0.0 239.255.255.255
• Reserved for future use 240.0.0.0
  255.255.255.254
• Limited broadcast 255.255.255.255

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Classful Subnet Masks
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AND Operation

• AND operation uses truth value
• true true true
• true false false
• false false false
• AND operation used to extract subnet address from
  IP address

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Finding Subnet Address
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Subnets Special Addresses

• Some addresses are reserved for special purposes
• Reserved classful addresses (byte boundary)
• Zero in host octets for network address
• 255 in host octets for broadcast address
• Subnets not on byte boundaries
• Zeroes in host bits for network address
• Ones in host bits for broadcast address

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Subnets within Class B
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Subnets within Class C
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(No Transcript)
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Classless Inter-Domain Routing

• Classless Inter-Domain Routing (CIDR)
• More efficient use of routing table space
• Enables supernetting
• Pronounced cider
• Replaces A, B, and C class structure with number
  of set bits in subnet mask
• xxx.xxx.xxx.xxx/xx IP address /no.mask bits
• 192.168.0.113/16 equivalent of Class C address
• http//public.pacbell.net/dedicated/cidr.html

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(No Transcript)
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CIDR Subnet and Supernet
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Calculating Supernet IP
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Gateways

• Combination of software and hardware
• Facilitate communications between different
  networks and subnets
• Default gateway
• Every device on TCP/IP network should have one
• First receives outbound requests for other
  subnets
• Interprets inbound requests from other subnets
• Internet gateway (backbone) usually assigned IP
  with last octet of 1

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Illustration of Default Gateways
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Network Address Translation (NAT)

• Gateway for hiding internal IP address
• Flexibility in assigning IP addresses
• Internal IP addressany IP address
• External IP address
• Comes from pool of valid Internet IPs (permanent)
• Only used for duration of transmission
  (temporary)
• Provides a little additional security, since each
  transmission has new IP

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NAT Illustration
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More Terms

• Hypertext Markup Language (HTML)
• Formatting of text
• Used in Hypertext Transfer Protocol (http)
• Language of Web pages
• Intranet
• Within an enterprise
• Extranet
• Uses Internet-like services and protocols

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TCP/IP Mail Service

• Simple Mail Transfer Protocol (SMTP)
• Protocol responsible for moving messages from one
  mail server to another over TCP/IP-based networks
• Multipurpose Internet Mail Extensions (MIME)
• Allows for messages that contain no more than
  1000 ASCII characters
• Post Office Protocol (POP)
• Application layer protocol used to retrieve
  messages from a mail server
• Internet Mail Access Protocol (IMAP)

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Internet Mail Access Protocol (IMAP)

• Retrieve all or only a portion of any mail
  message
• Review their messages and delete them while the
  messages remain on the server
• Create sophisticated methods of organizing
  messages on the server
• Share a mailbox in a central location

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Additional TCP/IP Utilities

• netstat
• nbstat
• nslookup
• whois
• traceroute
• ipconfig and winipcfg
• ifconfig

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Netstat

• -aProvides a list of all available TCP and UDP
  connections
• -eDisplays details about all the packets
• -nLists currently connected hosts according to
  their port and IP address
• -pAllows you to specify what type of protocol
  statistics to list
• Must be followed by a protocol specification (TCP
  or UDP)
• -rProvides a list of routing table information
• -sProvides statistics about each packet
  transmitted by a host, separated according to
  protocol type (IP,TCP, UDP, or ICMP)

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netstat Output
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nbtstat

• -aDisplays a machines name table given its
  NetBIOS name
• -ADisplays a machines name table given its IP
  address
• -rLists statistics about names that have been
  resolved
• -sDisplays a list of all the current NetBIOS
  sessions

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nslookup

• Allows you to query the DNS database
• Returns server and results data

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Whois

• Allows you to query this DNS registration
  database and obtain information about a domain

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Traceroute (Tracert)

• -dInstructs the traceroute command not to
  resolve IP addresses to host names
• -hSpecifies the maximum number of hops
• -wIdentifies a timeout

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traceroute Output
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Ipconfig

• /?Displays a list of switches
• /allDisplays complete TCP/IP configuration
• /releaseReleases DHCP
• /renewRenews DHCP

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ipconfig Output
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Winipcfg

• Windows 9x and Me operating systems

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Ifconfig

• -a
• down
• up

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ifconfig a Output
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Voice Over IP (VOIP)

• Also known as IP telephony
• Lower costs for voice calls
• toll bypass
• Supply new or enhanced features and applications
• Centralize voice and data network management

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Accessing VoIP from Phone
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VoIP Network
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VoIP Phone
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Chapter Summary

• Discuss methods of network design unique to
  TCP/IP networks, including subnetting, CIDR, and
  NAT
• Describe protocols used between mail clients and
  mail servers
• Explain the fundamental principles of using a
  TCP/IP network for packetized voice transmissions
• Employ multiple TCP/IP utilities for network
  discovery and troubleshooting