The InternetThe Internet

Just the FactsJust the Facts

ProtocolsProtocols

TCP/IP are the TRANSPORT protocols of TCP/IP are the TRANSPORT protocols of the Internetthe Internet

Services use TCP/IP to connect to other Services use TCP/IP to connect to other computers on Internetcomputers on Internet

TCP/IP use Network Interfaces (Ethernet, TCP/IP use Network Interfaces (Ethernet, Token Ring, ATM, Frame Relay, DSL, Token Ring, ATM, Frame Relay, DSL, DOCSIS (Cable modem), FDDI, ……DOCSIS (Cable modem), FDDI, ……

TCP/IP AddressingTCP/IP Addressing

Consists of 4 8-bit Numbers seperated by Consists of 4 8-bit Numbers seperated by dots.dots.

Must be associated with a subnet mask to Must be associated with a subnet mask to be complete.be complete.

Example:Example:– 10.24.244.56 IP Address10.24.244.56 IP Address– 255.255.0.0 Subnet Mask255.255.0.0 Subnet Mask– 10.24.0.0 Network Address10.24.0.0 Network Address

TCP/IP UseabilityTCP/IP Useability

To connect to other networks a router or To connect to other networks a router or default gateway must be specified.default gateway must be specified.

To convert names (google.com) to To convert names (google.com) to numbers (209.85.171.100) a Domain numbers (209.85.171.100) a Domain Name Server (DNS) must be specified.Name Server (DNS) must be specified.

TCP/IPv4 is (has) running out of TCP/IPv4 is (has) running out of addresses.addresses.

IPv6 uses 128-bit addresses. IPv6 uses 128-bit addresses.

IP Default ClasesIP Default ClasesClassClass RangeRange Subnet Subnet

AA 1.0.0.0 –1.0.0.0 –

126.255.255.255126.255.255.255255.0.0.0255.0.0.0

BB 128.0.0 –128.0.0 –

191.255.255.255191.255.255.255

255.255.0.0255.255.0.0

CC 192.0.0.0 –192.0.0.0 –

223.255.255.255223.255.255.255

255.255.255.0255.255.255.0

DD 224.0.0.0-224.0.0.0-

239.255.255.255239.255.255.255

Multicast Multicast

no Subnetno Subnet

EE 240.X.X.X -240.X.X.X - ExperimentalExperimental

Service ProtocolsService Protocols

ServiceService PortPort DescriptionDescription

HTTPHTTP 8080 Web Page DeliveryWeb Page Delivery

HTTPSHTTPS 443443 Secure Web Page DeliverySecure Web Page Delivery

SSLSSL Secure Socket Layer Secure Socket Layer provides Encryptionprovides Encryption

SMTPSMTP 2525 Mail Server to Mail Server Mail Server to Mail Server (i.e. sending e-mail)(i.e. sending e-mail)

POPPOP 110 110 Post Office Protocol Post Office Protocol (retrieveing E-mail to host)(retrieveing E-mail to host)

Service Protocols continuedService Protocols continuedServiceService PortPort DescriptionDescription

IMAPIMAP 143143 Internet Message Access Protocol Internet Message Access Protocol designed to keep messages on designed to keep messages on serverserver

POPsPOPs 995995 Secure POPSecure POP

IMAPsIMAPs 993993 Secure IMAPSecure IMAP

FTPFTP 2121 File Transfer Protocol (more File Transfer Protocol (more efficient than HTTP)efficient than HTTP)

NNTPNNTP 119119 Network News Transfer Protocol Network News Transfer Protocol (Discussion Groups)(Discussion Groups)

Service Protocols continuedService Protocols continued

ServiceService PortPort DescriptionDescription

TelnetTelnet 2323 Connect to a SHELL on a Connect to a SHELL on a remote computerremote computer

SSHSSH 2222 Securely connect to a SHELL Securely connect to a SHELL on a remote computeron a remote computer

PPPPPP Point to PointPoint to Point

PPPoEPPPoE Point to Point over EthernetPoint to Point over Ethernet

PPPoAPPPoA Point to Point over ATMPoint to Point over ATM

Internet NamingInternet Naming

.COM high-level domain is for Commercial .COM high-level domain is for Commercial CompaniesCompanies

.EDU for colleges and universities.EDU for colleges and universities

.ORG for non-profit organizations.ORG for non-profit organizations

.GOV for US Government.GOV for US Government

.MIL for US Military.MIL for US Military

Internet ConnectionsInternet Connections

Internet Service Providers (ISP) provide Internet Service Providers (ISP) provide connectionconnection

Asynchronous Digital Subscriber Line Asynchronous Digital Subscriber Line (ADSL) bigger download pipe.(ADSL) bigger download pipe.

Wireless is nice but has security issuesWireless is nice but has security issues

Satellite can reach anywhere but has large Satellite can reach anywhere but has large latencieslatencies

Internet Connection Sharing (98se, 2K,XP) Internet Connection Sharing (98se, 2K,XP)

Connections ContinuedConnections Continued

ISDN BRI: 2 data channels (64k), 1 ISDN BRI: 2 data channels (64k), 1 Control Channel (16k)Control Channel (16k)

Web Proxy Server: can improve Web Proxy Server: can improve performance and filter contentperformance and filter content

Proxy set for IE in Connections tab of Proxy set for IE in Connections tab of Internet Tools or in IEInternet Tools or in IE

E-mail configuration requires Incoming E-mail configuration requires Incoming and Outgoing mail serversand Outgoing mail servers

BrowsersBrowsers

For the purposes of A+ the following are For the purposes of A+ the following are legitimate legitimate – Internet ExplorerInternet Explorer

Internet Connection FirewallInternet Connection Firewall

Blocks access to Programs/PortsBlocks access to Programs/Ports