Networking with TCP/IP Networking with TCP/IP and the Internetand the Internet

ObjectivesObjectives

Discuss additional details of TCP/IP addressing Discuss additional details of TCP/IP addressing and subprotocolsand subprotocolsComprehend the purpose and procedure for Comprehend the purpose and procedure for subnettingsubnettingUnderstand the history and uses of BOOTP, Understand the history and uses of BOOTP, DHCP, WINS, DNS, and host filesDHCP, WINS, DNS, and host filesEmploy multiple TCP/IP utilities for network Employ multiple TCP/IP utilities for network troubleshootingtroubleshootingUnderstand TCP/IP applications, such as Understand TCP/IP applications, such as Internet browsers, e-mail, and voice over IPInternet browsers, e-mail, and voice over IP

Addressing and Name Addressing and Name ResolutionResolution

IP AddressingIP Addressing An IP address is 32 bits in sizeAn IP address is 32 bits in size Every IP address is grouped into four 8-bit Every IP address is grouped into four 8-bit

octetsoctets Octets are separated by decimal pointsOctets are separated by decimal points Valid octet numbers range from 0 to 255 and Valid octet numbers range from 0 to 255 and

represent a binary addressrepresent a binary address

Addressing and Name Addressing and Name ResolutionResolution

IP Addressing (cont.)IP Addressing (cont.) Each address consists of two parts: network Each address consists of two parts: network

and hostand host The network portion of an address indicates The network portion of an address indicates

whether the device belongs to a Class A, B, whether the device belongs to a Class A, B, C, D, or E networkC, D, or E network

Some octet number are reserved for special Some octet number are reserved for special functionsfunctions

Addressing and Name Addressing and Name ResolutionResolution

Static addressStatic address IP address that is manually assigned to a IP address that is manually assigned to a

devicedevice

Dynamic addressDynamic address IP address that is assigned to a device through IP address that is assigned to a device through

DHCPDHCP

Dotted decimal notationDotted decimal notation ““Shorthand” convention used to represent IP Shorthand” convention used to represent IP

addresses and make them more easily addresses and make them more easily readable by peoplereadable by people

Network ClassesNetwork Classes

Figure 11-1: IP addresses and their classes

Network ClassesNetwork Classes

MulticastingMulticasting Allows one device to send data to a specific group of Allows one device to send data to a specific group of

devices (not the entire network segment)devices (not the entire network segment)

New addressing scheme is being developedNew addressing scheme is being developed IP version 6 (IPV6)IP version 6 (IPV6) will incorporate this new scheme will incorporate this new scheme

TABLE 11-1 Three commonly used classes of TCP/IP networks

SubnettingSubnetting

Process of subdividing a single class of network into Process of subdividing a single class of network into multiple, smaller networksmultiple, smaller networks

Figure 11-2: IP address before and after subnets

SubnettingSubnetting

Extended network prefixExtended network prefix The combination of an address’s network and The combination of an address’s network and

subnet informationsubnet information

Subnet maskSubnet mask Special 32-bit number that, when combined Special 32-bit number that, when combined

with a device’s IP address, informs the rest of with a device’s IP address, informs the rest of the network about the network class to which the network about the network class to which the device is onthe device is on

SubnettingSubnetting

Figure 11-3: Subnetted IP address and its subnet mask

SubnettingSubnetting

Figure 11-4: Subnetted network connected to the Internet

SubnettingSubnetting

Figure 11-5: Network with

several subnets

SubnettingSubnetting

Figure 11-6: Data traveling over subnets

GatewaysGateways

Combination of software and hardware that Combination of software and hardware that enable two different network segments to enable two different network segments to exchange dataexchange data

Every device on a TCP/IP-based network has a Every device on a TCP/IP-based network has a defaultdefault gatewaygateway First interprets its outbound requests to other subnets First interprets its outbound requests to other subnets

and then interprets its inbound requests from other and then interprets its inbound requests from other subnetssubnets

Core GatewaysCore Gateways Gateways that make up the Internet backboneGateways that make up the Internet backbone

GatewaysGateways

Figure 11-7: Use of default gateways

Network Address Translation (NAT)Network Address Translation (NAT)

Technique in Technique in which IP which IP addresses addresses are assigned are assigned a public IP a public IP address by address by an IP an IP gatewaygateway

Figure 11-8: NAT through an IP gateway

Sockets and PortsSockets and Ports

SocketSocket Logical address assigned to a specific Logical address assigned to a specific

process running on a host computerprocess running on a host computer The socket’s address combines the host The socket’s address combines the host

computer’s IP address with the computer’s IP address with the port numberport number associated with a processassociated with a process

Port numbers in the range of 0 to 1023 are Port numbers in the range of 0 to 1023 are called called well-known portswell-known ports

Sockets and PortsSockets and Ports

Table 11-2a: Commonly

used TCP/IP port numbers

Sockets and PortsSockets and Ports

Table 11-2b: Commonly used TCP/IP port numbers (cont.)

Sockets and PortsSockets and Ports

Figure 11-9: Virtual circuit for the Telnet service

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

Host nameHost name Symbolic name that describes a TCP/IP Symbolic name that describes a TCP/IP

devicedevice

DomainDomain Group of computers that belong to the same Group of computers that belong to the same

organization and have part of their IP organization and have part of their IP addresses in commonaddresses in common

Host FilesHost Files

Text file that associates TCP/IP host names with IP Text file that associates TCP/IP host names with IP addressesaddressesAliasAlias

Nickname for a node’s host nameNickname for a node’s host name

Figure 11-10: An example of a host file

Host FilesHost Files

On a UNIX-based computer a host file is:On a UNIX-based computer a host file is: Called Called hostshosts Located in the /etc directoryLocated in the /etc directory

On a Windows 9x computer, a host file:On a Windows 9x computer, a host file: Is called Is called lmhostslmhosts Must be located in the c:\windows directory in Must be located in the c:\windows directory in

order to be recognized by the operating order to be recognized by the operating systemsystem

Domain Name System (DNS)Domain Name System (DNS)

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

Figure 11-11: DNS server hierarchy by geography

Domain Name System (DNS)Domain Name System (DNS)

ResolversResolvers Hosts on the Internet that need to look up domain Hosts on the Internet that need to look up domain

name informationname information

Name serversName servers Servers that contain databases of names and Servers that contain databases of names and

their associated IP addressestheir associated IP addresses Each name server manages a group of device, Each name server manages a group of device,

collectively known as a collectively known as a zonezone

Configuring DNSConfiguring DNS

Figure 11-12: Internet Protocol

(TCP/IP) Properties dialog box in Windows

2000

Configuring DNSConfiguring DNS

Figure 11-13: DNS

Configuration properties tab

DNS Name SpaceDNS Name Space

Name spaceName space Refers to the actual database of Internet IP Refers to the actual database of Internet IP

addresses and their associated namesaddresses and their associated names Every name server holds a piece of the DNS Every name server holds a piece of the DNS

name spacename space At the highest level of the hierarchy sit the At the highest level of the hierarchy sit the

root serversroot servers

DNS Name SpaceDNS Name Space

Resource recordResource record Element of a DNS database stored on a name Element of a DNS database stored on a name

server that contains information about TCP/IP server that contains information about TCP/IP host names and their addresseshost names and their addresses

Address resource recordAddress resource recordType of resource record that maps the IP address Type of resource record that maps the IP address of an Internet-connected device to its domain of an Internet-connected device to its domain namename

Bootstrap Protocol (BOOTP)Bootstrap Protocol (BOOTP)

Service that simplifies IP address managementService that simplifies IP address management

Figure 11-14: The BOOTP process

Bootstrap Protocol (BOOTP)Bootstrap Protocol (BOOTP)

Thanks to BOOTP, a client does not have to Thanks to BOOTP, a client does not have to remember its own IP addressremember its own IP address Therefore, network administrators do not have to Therefore, network administrators do not have to

go to each workstation on a network and go to each workstation on a network and manually assign its IP addressmanually assign its IP address

This situation is ideal for This situation is ideal for diskless diskless workstationsworkstations

Dynamic Host Configuration Dynamic Host Configuration Protocol (DHCP)Protocol (DHCP)

Automated means of assigning a unique IP Automated means of assigning a unique IP address to every device on a networkaddress to every device on a network

Reasons for implementing DHCPReasons for implementing DHCP Reduce the time and planning spent on IP address Reduce the time and planning spent on IP address

managementmanagement Reduce the potential for errors in assigning IP Reduce the potential for errors in assigning IP

addressesaddresses Enable users to move their workstations and printers Enable users to move their workstations and printers

without having to change their TCP/IP configurationwithout having to change their TCP/IP configuration Make IP addressing transparent for mobile usersMake IP addressing transparent for mobile users

DHCP Leasing ProcessDHCP Leasing Process

LeaseLease Agreement between DHCP server and client on how long the Agreement between DHCP server and client on how long the

client will borrow a DHCP-assigned IP addressclient will borrow a DHCP-assigned IP address

Figure 11-15: DHCP lease agreement

Terminating a DHCP LeaseTerminating a DHCP Lease

A DHCP lease may expire based on the period A DHCP lease may expire based on the period established for it in the server configurationestablished for it in the server configuration

A DHCP lease may be manually terminated at any A DHCP lease may be manually terminated at any time from either the client’s TCP/IP configuration time from either the client’s TCP/IP configuration or the server’s DHCP configurationor the server’s DHCP configuration

In some instances, a user must terminate a leaseIn some instances, a user must terminate a lease

ReleaseRelease The act of terminating a DHCP leaseThe act of terminating a DHCP lease

Windows Internet Naming Service Windows Internet Naming Service (WINS)(WINS)

Provides a means of resolving NetBIOS Provides a means of resolving NetBIOS names with IP addressesnames with IP addresses

WINS offers several advantagesWINS offers several advantages Guarantees a unique NetBIOS name is used Guarantees a unique NetBIOS name is used

for each computer on a networkfor each computer on a network Support for DHCPSupport for DHCP Better network performanceBetter network performance

Windows Internet Naming Service Windows Internet Naming Service (WINS)(WINS)

Figure 11-16: Advanced

TCP/IP Settings

dialog box in Windows

2000

Simple Mail Transfer Protocol(SMTP) Simple Mail Transfer Protocol(SMTP) and Post Office Protocol (POP)and Post Office Protocol (POP)

SMTPSMTP Responsible for moving messages from one Responsible for moving messages from one

e-mail server to anothere-mail server to another

POPPOP Provides centralized storage for e-mail Provides centralized storage for e-mail

messagesmessages

Internet Mail Access Protocol Internet Mail Access Protocol (IMAP)(IMAP)

Mail storage and manipulation protocol Mail storage and manipulation protocol that depends on SMTP’s transport systemthat depends on SMTP’s transport system Developed as a more sophisticated Developed as a more sophisticated

alternative to POPalternative to POP Most current version is version 4 (IMAP4)Most current version is version 4 (IMAP4)

Biggest advantage of IMAP4 over POP relates to Biggest advantage of IMAP4 over POP relates to the fact users can store messages on the mail the fact users can store messages on the mail serverserver

Additional Features of IMAP4Additional Features of IMAP4

Users can retrieve all or only a portion of any Users can retrieve all or only a portion of any mail messagemail messageUsers can review their messages and delete Users can review their messages and delete them while the messages remain on the serverthem while the messages remain on the serverUsers can create sophisticated methods of Users can create sophisticated methods of organizing messages on the serverorganizing messages on the serverUsers can share a mailbox in a central locationUsers can share a mailbox in a central locationIMAP4 can provide better security than POP IMAP4 can provide better security than POP because it supports authenticationbecause it supports authentication

Hypertext Transport Protocol Hypertext Transport Protocol (HTTP)(HTTP)

Language that Web clients and servers Language that Web clients and servers use to communicateuse to communicate

Forms the backbone of the WebForms the backbone of the Web

Hypertext Markup Language (HTML)Hypertext Markup Language (HTML) Language that defines formatting standards Language that defines formatting standards

for Web documentsfor Web documents

Hypertext Transport Protocol Hypertext Transport Protocol (HTTP)(HTTP)

Figure 11-18: Web client/server transmission using HTTP

Packet Internet Groper (PING)Packet Internet Groper (PING)

Troubleshooting utility that can verify TCP/IP is Troubleshooting utility that can verify TCP/IP is installed, bound to the NIC, configured correctly, installed, bound to the NIC, configured correctly, and communicating with the networkand communicating with the network

An An echo requestecho request is a signal sent out to another is a signal sent out to another computercomputer

An An echo replyecho reply is the other computer’s is the other computer’s response signalresponse signal

Process of sending this signal back and forth is Process of sending this signal back and forth is known as known as pingingpinging

Packet Internet Groper (PING)Packet Internet Groper (PING)

Figure 11-19: Example of successful and unsuccessful PING

NetstatNetstat

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

Figure 11-20: Output of a simple netstat command

NslookupNslookup

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

Figure 11-21: Output of a simple ns lookup command

TracerouteTraceroute

Uses ICMP to trace path from one networked node to anotherUses ICMP to trace path from one networked node to another

Also known as Also known as tracerttracert on Windows machines on Windows machines

Figure 11-22: Output of a traceroute command

IpconfigIpconfig

TCP/IP administration utility for use with Windows NT and Windows TCP/IP administration utility for use with Windows NT and Windows 2000 operating systems2000 operating systems

Figure 11-23: Output of an ipconfig command on a Windows 2000 workstation

IfconfigIfconfig

TCP/IP configuration and management utility used on UNIX systemsTCP/IP configuration and management utility used on UNIX systems

Figure 11-26: Detailed information available through ifconfig

Internet ServicesInternet Services

World Wide Web (WWW, or Web)World Wide Web (WWW, or Web) Collection of internetworked servers that share Collection of internetworked servers that share

resources and exchange information according to resources and exchange information according to specific protocols and formatsspecific protocols and formats

BrowserBrowserSoftware that provides clients with a simple, graphical Software that provides clients with a simple, graphical interface to the Webinterface to the Web

World Wide WebWorld Wide Web

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

Unqualified host nameUnqualified host name Host name minus its prefix and suffixHost name minus its prefix and suffix

E-mail andE-mail andFile Transfer Protocol (FTP)File Transfer Protocol (FTP)

E-mailE-mail Currently, e-mail is most relied-upon Internet service you will manageCurrently, e-mail is most relied-upon Internet service you will manage

FTPFTP Manages files transfers between TCP/IP hostsManages files transfers between TCP/IP hosts

Figure 11-27: FTP login screen

Trivial File Transfer Protocol (TFTP) Trivial File Transfer Protocol (TFTP) and Gopherand Gopher

TFTPTFTP TCP/IP Application layer protocol that enables TCP/IP Application layer protocol that enables

file transfers between computersfile transfers between computers

GopherGopher Text-based utility that allows you to navigate Text-based utility that allows you to navigate

through a series of menus to find and read through a series of menus to find and read specific filesspecific files

Newsgroups and E-commerceNewsgroups and E-commerce

NewsgroupsNewsgroups Provides means of conveying messages in which Provides means of conveying messages in which

information is distributed to a wide group of users information is distributed to a wide group of users at onceat once

Network News Transfer Protocol (NNTP)Network News Transfer Protocol (NNTP)Supports process of reading newsgroup messages, Supports process of reading newsgroup messages, posting new messages, and transferring news files posting new messages, and transferring news files between news serversbetween news servers

E-commerceE-commerce Means of conducting business over the WebMeans of conducting business over the Web

Chapter SummaryChapter Summary

Every device on a TCP/IP-based network must have a Every device on a TCP/IP-based network must have a unique IP address to ensure reliable data deliveryunique IP address to ensure reliable data delivery

In addition to Class A, B, and C networks, Class D and E In addition to Class A, B, and C networks, Class D and E networks exist, although consumers and companies do not networks exist, although consumers and companies do not use themuse them

To use IP addresses more efficiently, the concept of To use IP addresses more efficiently, the concept of subnetting was applied to the Internet in the mid-1980ssubnetting was applied to the Internet in the mid-1980s

Gateways are a combination of software and hardware Gateways are a combination of software and hardware that enable two different network segments to exchange that enable two different network segments to exchange datadata

A socket is a logical address assigned to a specific A socket is a logical address assigned to a specific process running on a host computerprocess running on a host computer

Chapter SummaryChapter SummaryThe use of port numbers simplifies TCP/IP The use of port numbers simplifies TCP/IP communicationscommunications

Every host belongs to a domainEvery host belongs to a domain

In the mid-1980s, the Network Information Center In the mid-1980s, the Network Information Center (NIC) at Stanford Research Institute devised a (NIC) at Stanford Research Institute devised a hierarchical way of tracking domain names and their hierarchical way of tracking domain names and their addresses, called the Domain Name System (DNS)addresses, called the Domain Name System (DNS)

To ease IP address management, a service called To ease IP address management, a service called Bootstrap Protocol (BOOTP) was developed in the Bootstrap Protocol (BOOTP) was developed in the mid-1980smid-1980s

Dynamic Host Configuration Protocol (DHCP) is an Dynamic Host Configuration Protocol (DHCP) is an automated means of assigning a unique IP address to automated means of assigning a unique IP address to every device on a networkevery device on a network

Chapter SummaryChapter Summary

Windows Internet Naming Service (WINS) provides a means Windows Internet Naming Service (WINS) provides a means of resolving NetBIOS names with IP addressesof resolving NetBIOS names with IP addresses

TCP/IP is a suite of protocols, commonly called subprotocolsTCP/IP is a suite of protocols, commonly called subprotocols

TCP/IP carries the highest potential of causing problems TCP/IP carries the highest potential of causing problems because it requires the most planning and post-installation because it requires the most planning and post-installation configurationconfiguration

TCP/IP comes with a complete set of troubleshooting tools TCP/IP comes with a complete set of troubleshooting tools that can help you to track down most TCP/IP-related problemsthat can help you to track down most TCP/IP-related problems

There are numerous Internet services, including the World There are numerous Internet services, including the World Wide Web, e-mail, File Transfer Protocol, gopher, Wide Web, e-mail, File Transfer Protocol, gopher, newsgroups, e-commerce, and VoIPnewsgroups, e-commerce, and VoIP