109.1 Fundamentals of internet protocols

Weight: 4

Description: Candidates should demonstrate a proper understanding of TCP/IP network fundamentals.

Key Knowledge Areas:

• Demonstrate an understanding of network masks and CIDR notation
• Knowledge of the differences between private and public “dotted quad” IP addresses
• Knowledge about common TCP and UDP ports and services (20, 21, 22, 23, 25, 53, 80, 110, 123, 139, 143, 161, 162, 389, 443, 465, 514, 636, 993, 995)
• Knowledge about the differences and major features of UDP, TCP and ICMP
• Knowledge of the major differences between IPv4 and IPv6
• Knowledge of the basic features of IPv6

Terms and Utilities:

/etc/services
IPv4, IPv6
Subnetting
TCP, UDP, ICMP

io interface port as network hw

Parallel Line Interface Protocol (PLIP) - parallel port
Point-to-Point Protocol (PPP) - USB or RS-232 serial port

network hw

Ethernet - twisted-pair cabling 10BaseT/100BaseT/1000BaseT/10GBaseT
Token Ring
LocalTalk
Fiber Distributed Data Interface (FDDI)
High-Performance Parallel Interface (HIPPI)
Fiber Channel

Wi-Fi
802.11b 11Mbps
802.11a/802.11g 54Mbps
802.11n 300Mbps

Wi-Fi encryption
Wired Equivalent Privacy (WEP) weak
Protected Access (WPA) / WPA2

Switches full-duplex transmission
Hubs half-duplex transmission

network stack

A protocol stack is a set of software that converts and encapsulates data between layers of abstraction.

IP The Internet Protocol (IP)
- core protocol in TCP/IP networking
- Internet-layer L2
- “best effort” method for transferring packets between computers
- not guaranteed to reach their destination
- Packets may also arrive out of order or corrupted

IPv6
- IPv4 uses 32-bit addresses, but IPv6 uses 128-bit addresses providing addresses for up to 3.4 × 1038 devices
- new feature stateless address auto-configuration (SLAAC) similar as DHCP in Ipv4

ICMP The Internet Control Message Protocol (ICMP)
- simple protocol for communicating data
- ping to check node access availability

UDP The User Datagram Protocol (UDP)
- simplest of the common transport-layer L3 TCP/IP protocols
- not correct for out-of-order packets, guarantee delivery
- faster than TCP
- used for DNS/NFS

TCP The Transmission Control Protocol (TCP)
- create full connections with error checking and correction
- imposes a small performance penalty
- used for SMTP/HTTP/FTP

address class

Class Address range Reserved private addresses
A 1.0.0.0-127.255.255.255 10.0.0.0-10.255.255.255
B 128.0.0.0-191.255.255.255 172.16.0.0-172.31.255.255
C 192.0.0.0-223.255.255.255 192.168.0.0-192.168.255.255
D 224.0.0.0-239.255.255.255 none
E 240.0.0.0-255.255.255.255 none

CIDR

address 172.30.9.102 and netmask 255.255.128.0 = 172.30.0.0/17
10101100 00011110 00001001 01100110
11111111 11111111 10000000 00000000

network port

/etc/services
21 TCP FTP
22 TCP Secure Shell (SSH) SFTP
23 TCP Telnet
25 TCP Simple Mail Transfer Protocol (SMTP)
53 TCP and UDP Domain Name System (DNS)
80 TCP Hypertext Transfer Protocol (HTTP)
110 TCP Post Office Protocol version 3 (POP3)
143 TCP Interactive Mail Access Protocol (IMAP)
161 UDP SNMP agent
162 UDP SNMP trap
389 TCP LDAP