Networking Essentials – Eric Vanderburg © 2005

TCP/IP & IP AddressingTCP/IP & IP AddressingChapter 3Chapter 3

Networking Essentials – Eric Vanderburg © 2005

TCP/IP OriginTCP/IP Origin Created by the DoD (Department of Created by the DoD (Department of

Defense) ARPA (Advanced Research Defense) ARPA (Advanced Research Projects Agency) in order to have a Projects Agency) in order to have a network that could survive a network that could survive a nuclear attack. nuclear attack.

Networking Essentials – Eric Vanderburg © 2005

Protocol SuiteProtocol Suite FTP (File Transfer Protocol)FTP (File Transfer Protocol) TFTP (Trivial File Transfer Protocol)TFTP (Trivial File Transfer Protocol) NFS (Network File System) – network NFS (Network File System) – network

sharingsharing SMTP (Simple Mail Transfer Protocol)SMTP (Simple Mail Transfer Protocol) Telnet (Terminal Emulation Protocol)Telnet (Terminal Emulation Protocol) SNMP (Simple Network Management SNMP (Simple Network Management

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

Networking Essentials – Eric Vanderburg © 2005

Protocol SuiteProtocol Suite HTTP (Hypertext Transfer Protocol)HTTP (Hypertext Transfer Protocol) NTP (Network Time Protocol)NTP (Network Time Protocol) POP (Post Office Protocol)POP (Post Office Protocol) NNTP (Network News Transfer Protocol)NNTP (Network News Transfer Protocol) ARP (Address Resolution Protocol) – Find ARP (Address Resolution Protocol) – Find

MAC from IPMAC from IP RARP (Reverse Address Resolution RARP (Reverse Address Resolution

Protocol) – MAC to IP for diskless Protocol) – MAC to IP for diskless workstationsworkstations

ICMP (Internet Control Message Protocol)ICMP (Internet Control Message Protocol)

Networking Essentials – Eric Vanderburg © 2005

PortsPorts 20, 21 FTP20, 21 FTP 23 Telnet23 Telnet 25 SMTP25 SMTP UDP 53 DNSUDP 53 DNS 69 TFTP69 TFTP 80 HTTP80 HTTP 123 NTP123 NTP 110 POP3110 POP3 119 NNTP119 NNTP 161 SNMP161 SNMP

Networking Essentials – Eric Vanderburg © 2005

HandshakesHandshakes A: SYN connection request is sentA: SYN connection request is sent B: ACK to SYN with sequence + 1 and B: ACK to SYN with sequence + 1 and

sends own SYNsends own SYN A: ACK to B’s SYN with sequence + 1A: ACK to B’s SYN with sequence + 1

Networking Essentials – Eric Vanderburg © 2005

SubnettingSubnetting Find Hosts & Subnets from a given Find Hosts & Subnets from a given

subnet masksubnet mask Find the subnet mask for a required Find the subnet mask for a required

number of hosts or subnetsnumber of hosts or subnets Determine which network a host is Determine which network a host is

on. on. Determine the broadcast address Determine the broadcast address

for the network a host belongs to. for the network a host belongs to. CIDR Notation (ex: /24 )CIDR Notation (ex: /24 )

Networking Essentials – Eric Vanderburg © 2005

VLSM (Variable Length Subnet VLSM (Variable Length Subnet Masks)Masks)

Essentially subnets the subnetsEssentially subnets the subnets Not supported by some routing Not supported by some routing

protocols such as RIP and IGRPprotocols such as RIP and IGRP Start with the largest and work your Start with the largest and work your

way downway down

Networking Essentials – Eric Vanderburg © 2005

SummarizationSummarization Routers that know about a number Routers that know about a number

of addresses can summarize them of addresses can summarize them by advertising a larger range by advertising a larger range instead of many smaller ranges. instead of many smaller ranges.

Only works when the router knows Only works when the router knows about all networks in a rangeabout all networks in a range

Networking Essentials – Eric Vanderburg © 2005

Remote HostsRemote Hosts Client contacts default gatewayClient contacts default gateway Default gateway recreates the data Default gateway recreates the data

with a new IP header and sends it with a new IP header and sends it offoff

Receiving router APRs the host to Receiving router APRs the host to get its MAC and creates a new get its MAC and creates a new frame to send to it. frame to send to it.

Networking Essentials – Eric Vanderburg © 2005

HexidecimalHexidecimal Hex numbers Hex numbers

convert to 4 convert to 4 bits. (1 nibble)bits. (1 nibble)

Networking Essentials – Eric Vanderburg © 2005

AcronymsAcronyms ARP, Address Resolution ProtocolARP, Address Resolution Protocol CIDR, Classless Inter-Domain RoutingCIDR, Classless Inter-Domain Routing DNS, Domain Name SystemDNS, Domain Name System FTP, File Transfer ProtocolFTP, File Transfer Protocol ISN, Initial Sequence NumberISN, Initial Sequence Number ICMP, Internet Control Message ProtocolICMP, Internet Control Message Protocol TCP, Transmission Control ProtocolTCP, Transmission Control Protocol TTL, Time To LiveTTL, Time To Live TFTP, Trivial File Transfer ProtocolTFTP, Trivial File Transfer Protocol UDP, User Datagram ProtocolUDP, User Datagram Protocol VLSM, Variable Length Subnet MaskingVLSM, Variable Length Subnet Masking