– General Linux 2 – Fundamentals of TCP/IP [4] (Linux Professional Institute Certification) a .˜. /V\ // \\ @._.@ by: geoffrey robertson geoffrey@zip.com.au $Id: gl2.112.1.slides.tex,v 1.1 2003/09/10 01:40:47 geoffr Exp $ c 2003 Geoffrey Robertson. Permission is granted to make and distribute verbatim copies or modified versions of this document provided that this copyright notice and this permission notice are preserved on all copies under the terms of the GNU General Public License as published by the Free Software Foundation—either version 2 of the License or (at your option) any later version. a Copyright 1 (2.2) Networking Fundamentals [14] 1.112.1 Fundamentals of TCP/IP [4] 1.112.3 TCP/IP configuration and troubleshooting [7] 1.112.4 Configure Linux as a PPP client [3] 2 Fundamentals of TCP/IP [4] Objective Candidates should demonstrate a proper understanding of network fundamentals. This objective includes the understanding of IP-addresses, network masks and what they mean (i.e. determine a network and broadcast address for a host based on its subnet mask in ”dotted quad” or abbreviated notation or determine the network address, broadcast address and netmask when given an IP-address and number of bits). It also covers the understanding of the network classes and classless subnets (CIDR) and the reserved addresses for private network use. It includes the understanding of the function and application of a default route. 3 It also includes the understanding of basic internet protocols (IP, ICMP, TCP, UDP) and the more common TCP and UDP ports (20, 21, 23, 25, 53, 80, 110, 119, 139, 143, 161). 4 Fundamentals of TCP/IP [4] Key files, terms, and utilities /etc/services ftp telnet host ping dig traceroute whois 5 Fundamentals of TCP/IP [4] Resources of interest TCP/IP Illustrated, Volume 1 The Protocols by W. Richard Stevens Addison Wesley LPIC 1 Certification Bible Angie Nash and Jason Nash Hungry Minds 6 IP addressing This objective includes the understanding of IP-addresses, network masks and what they mean (i.e. determine a network and broadcast address for a host based on its subnet mask in ”dotted quad” or abbreviated notation or determine the network address, broadcast address and netmask when given an IP-address and number of bits). 7 IP Address Classes (Classic) 8 IP Address Classes (Classic) Class A - 255.0.0.0 00000000.00000000.00000000.00000000 - 0.0.0.0 01111111.11111111.11111111.11111111 - 127.255.255.255 8-a IP Address Classes (Classic) Class A - 255.0.0.0 00000000.00000000.00000000.00000000 - 0.0.0.0 01111111.11111111.11111111.11111111 - 127.255.255.255 Class B - 255.255.0.0 10000000.00000000.00000000.00000000 - 128.0.0.0 10111111.11111111.11111111.11111111 - 191.255.255.255 8-b IP Address Classes (Classic) Class A - 255.0.0.0 00000000.00000000.00000000.00000000 - 0.0.0.0 01111111.11111111.11111111.11111111 - 127.255.255.255 Class B - 255.255.0.0 10000000.00000000.00000000.00000000 - 128.0.0.0 10111111.11111111.11111111.11111111 - 191.255.255.255 Class C - 255.255.255.0 11000000.00000000.00000000.00000000 - 192.0.0.0 11011111.11111111.11111111.11111111 - 223.255.255.255 8-c IP Address - Loopback Reserved Space 127.0.0.0 — 127.255.255.255 127.0.0.1 localhost 9 IP Address - Private Networks There are IP ranges set aside for privite address spaces. These should not be made visible on the internet. Class A 10.0.0.0 --- 10.255.255.255 Class B 172.16.0.0 --- 172.32.255.255 Class C 192.168.0.0 --- 192.168.255.255 10 IP Address - Subneting Network: 192.168.192.0 Subnet: 255.255.255.224 11 IP Address - Default Route # route add default gw 192.168.1.1 12 DoD Layer Model Application ftp, telnet, mail, http protocols Transport TCP , UDP protocols Network IP, ICMP, IGMP protocols Link Ethernet, Token Ring, FDDI 13 Basic Internet Protocols IP ICMP TCP UDP 14 Ports and Port Numbers Listing the Ports $ less /etc/services ftp 21/tcp ftp 21/udp ssh 22/tcp 22/udp ssh telnet 23/tcp telnet 23/udp # 24 - private mail system 25/tcp smtp smtp 25/udp time 37/tcp 15 fsp fspd # SSH Remote Login Protocol # SSH Remote Login Protocol mail mail timserver Ports and Port Numbers FTP 20, 21 Telnet 23 SSH 22 smtp 25 DNS 53 http 80 pop3 110 nntp 119 netbios 137, 138, 139 imap2 143 snmp 161 16 Port Number vRanges 1-255 Original reserved ports (till 1992) (256-1023 UNIX) 1-1023 Well Known or Famous Port Numbers - Reserved 1024-65535 Unprivileged 17 The End √ √ √ √ √ √ √ √ √ • • • • • • • • • (2.2) Networking Fundamentals [14] . . . . . . . . Fundamentals of TCP/IP [4] . . . . . . . . . . . . . IP addressing . . . . . . . . . . . . . . . . . . . . . IP Address Classes (Classic) . . . . . . . . . . . . . IP Address - Loopback . . . . . . . . . . . . . . . . IP Address - Private Networks . . . . . . . . . . . . IP Address - Subneting . . . . . . . . . . . . . . . . IP Address - Default Route . . . . . . . . . . . . . . DoD Layer Model . . . . . . . . . . . . . . . . . . 18 2 3 7 8 9 10 11 12 13 √ √ √ √ • • • • Basic Internet Protocols . . . . . . . . . . . . . . . Ports and Port Numbers . . . . . . . . . . . . . . . Ports and Port Numbers . . . . . . . . . . . . . . . Port Number vRanges . . . . . . . . . . . . . . . . 14 15 16 17 19