Network+ Guide to Networks Chapter 3

Network+ Guide to Networks Eighth Edition - Chapter 3

• Chapter 3 focuses on addressing on networks.
• Objectives include finding and explaining MAC addresses, configuring TCP/IP settings, explaining ports and sockets, describing domain names and name resolution, and troubleshooting network addresses using command-line tools.
• Four addressing methods exist: Data Link layer MAC address, Network layer IP address (IPv4 and IPv6), Transport layer port numbers and Application layer FQDNs, computer names, and host names.
• MAC addresses are 48 bits, written as six hexadecimal numbers separated by colons.
• MAC addresses are also known as the physical address. The first 24 bits are the Organisationally Unique Identifier (OUI) or manufacturer ID, assigned by IEEE.
• The last 24 bits make up the extension identifier or device ID. Manufacturers assign a unique device ID to each Network Interface Card (NIC).
• IPv4 addresses are 32 bits, written as four decimal numbers (octets) ranging from 0 to 255. IPv6 addresses are 128 bits, written as eight blocks of hexadecimal numbers separated by colons.
• Static IPv4 addresses are assigned manually by network administrators. Dynamic IPv4 addresses are automatically assigned by a Dynamic Host Configuration Protocol (DHCP) server.
• TCP/IP settings on a computer can be viewed in the Control Panel's Network and Sharing Center.
• Gateway devices allow nodes to access external networks.
• Subnet masks define the network and host portions of an IP address.
• DNS servers track computer names and their IP addresses.
• Network Address Translation (NAT) is a technique used to conserve public IP addresses.
• Port Address Translation (PAT) assigns TCP port numbers to ongoing sessions between a local host and an internet host.
• Two variations of NAT exist: SNAT (Static NAT) and DNAT (Dynamic NAT).
• IPv6 addresses are 128 bits, written as eight blocks of hexadecimal numbers separated by colons.
• Leading zeros in hexadecimal blocks can be eliminated. Blocks of all zeros can be represented with double colons (::), with only one set of colons used per IP address.
• IPv6 terminology includes link (local link), interface, dual stacked, tunneling, and neighbors.
• IPv6 addresses include Unicast (global and link-local), multicast, and anycast.
• Various types of IPv6 addresses are described.
• Auto-configuration enables computers to automatically configure their own link local IP addresses.
• DHCP scope is a range of IP addresses for client assignment.
• Port numbers are categorized into well-known (0-1023), registered (1024-49151), and dynamic / private (49152-65535).
• Protocols not yet covered include TFTP, NTP, LDAP, SMB, SIP, and H.323.
• DNS (Domain Name System) allows for character-based names instead of numeric IP addresses. FQDNs include top-level domains (TLDs).
• ICANN (Internet Corporation for Assigned Names and Numbers) controls top-level domains.
• Name resolution finds IP addresses based on known FQDNs.
• DNS is a client-server system with namespaces (entire collection of computer names and associated IP addresses).
• Name servers hold databases with hierarchical organization. Resolvers are DNS clients that request information from name servers.
• Organizations manage their own DNS authoritative servers for public access.
• Domains managed by an organization are called DNS zones.
• Common DNS server types include primary (authoritative), secondary (backup), caching, and forwarding types.
• Troubleshooting may involve checking time sources using w32tm/query /source.
• DHCP issues may involve insufficient scope or lease times.
• Troubleshooting tools are described (ping, ipconfig, ifconfig, nslookup, dig) along with detailed examples and information.