Networking with TCPIP and the Application Layers

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• Networking with TCP/IP and the Application Layers

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Sockets and Ports

• Socket
• Logical address assigned to a specific process
  running on a host computer
• The sockets address combines the host computers
  IP address with the port number associated with a
  process
• Port numbers in the range of 0 to 1023 are called
  well-known ports

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Sockets and Ports
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Sockets and Ports
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Host Names and Domain Name System (DNS)

• Host name
• Symbolic name that describes a TCP/IP device
• Domain
• Group of computers that belong to the same
  organization and have part of their IP addresses
  in common

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Domain Names

• Symbolic name that identifies an organization
• Top-level domains (TLDs)
• Highest-level category used to distinguish domain
  names
• A TLD is known as the domain suffix

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Domain Names
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Host Files

• Text file that associates TCP/IP host names with
  IP addresses
• Alias
• Nickname for a nodes host name

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Domain Name System (DNS)

• Hierarchical way of tracking domain names and
  their addresses, devised in the mid-1980s

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Domain Name System (DNS)

• Resolvers
• Hosts on the Internet that need to look up domain
  name information
• Name servers
• Servers that contain databases of names and their
  associated IP addresses
• Each name server manages a group of device,
  collectively known as a zone

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Configuring DNS
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DNS Name Space

• Name space
• Refers to the actual database of Internet IP
  addresses and their associated names
• Every name server holds a piece of the DNS name
  space
• At the highest level of the hierarchy sit the
  root servers
• Visit http//www.icann.org/
• And http//www.newroot.com/root-servers.htm

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DNS Name Space

• Resource record
• Element of a DNS database stored on a name server
  that contains information about TCP/IP host names
  and their addresses
• Address resource record
• Type of resource record that maps the IP address
  of an Internet-connected device to its domain name

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Dynamic Host Configuration Protocol (DHCP)

• Automated means of assigning a unique IP address
  to every device on a network
• Reasons for implementing DHCP
• Reduce the time and planning spent on IP address
  management
• Reduce the potential for errors in assigning IP
  addresses
• Enable users to move their workstations and
  printers without having to change their TCP/IP
  configuration
• Make IP addressing transparent for mobile users

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DHCP Leasing Process

• Lease
• Agreement between DHCP server and client on how
  long the client will borrow a DHCP-assigned IP
  address

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Terminating a DHCP Lease

• A DHCP lease may expire based on the period
  established for it in the server configuration
• A DHCP lease may be manually terminated at any
  time from either the clients TCP/IP
  configuration or the servers DHCP configuration
• In some instances, a user must terminate a lease
• Release
• The act of terminating a DHCP lease

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Windows Internet Naming Service (WINS)

• Provides a means of resolving NetBIOS names with
  IP addresses
• WINS offers several advantages
• Guarantees a unique NetBIOS name is used for each
  computer on a network
• Support for DHCP
• Better network performance

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Windows Internet Naming Service (WINS)
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Review of TCP/IP Subprotocols

• Internet Protocol (IP)
• Transport Control Protocol (TCP)
• User Datagram Protocol (UDP)
• Internet Control Message Protocol (ICMP)
• Address Resolution Protocol (ARP)
• Telnet
• File Transfer Protocol (FTP)
• Simple Network Management Protocol (SNMP)

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Simple Mail Transfer Protocol (SMTP)

• SMTP
• Responsible for moving messages from one e-mail
  server to another

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Internet Mail Access Protocol (IMAP)

• Mail storage and manipulation protocol that
  depends on SMTPs transport system

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Hypertext Transport Protocol (HTTP)

• Language that Web clients and servers use to
  communicate
• Forms the backbone of the Web
• Hypertext Markup Language (HTML)
• Language that defines formatting standards for
  Web documents

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Hypertext Transport Protocol (HTTP)
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Network Time Protocol (NTP)

• Used to synchronize the clocks of a computers on
  a network
• Very simple protocol
• Belongs to Application Layer of TCP/IP Model
• Depends on UDP

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TCP/IP Troubleshooting

• Of all network protocols, TCP/IP is most likely
  to cause problems because it requires the most
  planning and post-installation configuration
• Be aware of the troubleshooting tools and their
  switches
• These troubleshooting utilities can be accessed
  from the command prompt on a server or client
  running TCP/IP

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Packet Internet Groper (PING)

• Troubleshooting utility that can verify TCP/IP is
  installed, bound to the NIC, configured
  correctly, and communicating with the network
• An echo request is a signal sent out to another
  computer
• An echo reply is the other computers response
  signal
• Process of sending this signal back and forth is
  known as pinging

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Netstat

• Netstat utility display TCP/IP statistics and
  details about TCP/IP components and connections
  on a host

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Nbstat

• The nbstat utility can provide information about
  NetBIOS statistics and resolve NetBIOS names to
  their IP addresses
• In other words, if you know the NetBIOS name of a
  workstation, you can use nbstat to determine its
  IP address
• Nbstat is useful on networks that run
  Windows-based operating systems and NetBIOS

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Nslookup

• Allows you to look up the DNS host name of a
  network node by specifying its IP address, or
  vice versa

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Traceroute

• Uses ICMP to trace path from one networked node
  to another
• Also known as tracert on Windows machines

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Ipconfig

• TCP/IP administration utility for use with
  Windows NT and Windows 2000 operating systems

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Winipcfg

• This utility performs the same TCP/IP
  configuration management as the ipconfig utility,
  but also applies to Windows 9x and Me operating
  systems

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Winipcfg
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Internet Services

• World Wide Web (WWW, or Web)
• Collection of internetworked servers that share
  resources and exchange information according to
  specific protocols and formats
• Browser
• Software that provides clients with a simple,
  graphical interface to the Web

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World Wide Web

• Uniform Resource Locator (URL)
• Standard means of identifying every Web page

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File Transfer Protocol (FTP)

• FTP - Manages files transfers between TCP/IP hosts

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E-commerce

• E-commerce
• Means of conducting business over the Web