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Networking computers

Networking computers. Unit objectives: Describe how various types of addresses are used to identify devices on a network Create client network connections through wired, wireless, and dial-up methods. Topic A. Topic A: Addressing Topic B: Client configuration. Network protocol.

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Networking computers

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  1. Networking computers Unit objectives: • Describe how various types of addresses are used to identify devices on a network • Create client network connections through wired, wireless, and dial-up methods

  2. Topic A • Topic A: Addressing • Topic B: Client configuration

  3. Network protocol • Communication language between network devices • Sends data in packets • Common network LAN protocols used in Windows • TCP/IP • IPX/SPX • AppleTalk • NetBEUI

  4. Addressing • MAC address • IPv4 address • IPv6 address • Character-based name

  5. Identifying addresses

  6. MAC address Also known as: Physical address Adapter address Ethernet address Unique value: Expressed as 6 pairs of hexadecimal numbers Often separated by hyphens or colons continued

  7. MAC address, continued Address contains: Manufacturer ID Unique number MAC addresses don’t change Used on LAN: Functions at OSI Data Link layer All hosts on LAN communicate by their MAC addresses MAC addresses alone can’t be used to communicate between two computers on different LANs

  8. IPv4 address 32 bits long 4 bytes separated by periods; each part called an octet Largest binary 11111111 = 255 4.3 billion potential IP addresses Divided into two parts: Network ID Host ID

  9. Classful IPv4 addresses

  10. APIPA • Automatic Private IP Addressing (APIPA) • 169.254.0.0 network • Windows OSs, and Windows Server 2000 & later, auto-generate APIPA addresses when necessary

  11. IPv6 address 128-bit address 16 bytes Displayed in hexadecimal Group address in hexadecimal, 2 bytes at a time, separated by colons (:) 3FFE:FFFF:0000:2F3B:02AA:00FF:FE28:9C5A Can remove leading zeros Can compress address by using double colons (::) for bytes with all zeros 3FFE:FFFF::2F3B:02AA:00FF:FE28:9C5A

  12. IPv6 address types Unicast Link-local IPv6 version of IPv4’s APIPA Self-assigned using Neighbor Discovery process Starts with FE8, FE9, FEA, or FEB Site-local (FEC0::/10) – deprecated Unique local address IPv6 version of IPv4 private address Begins with FC or FD continued

  13. IPv6 address types, continued Global unicast IPv6 version of IPv4 public address Identified for a single interface Routable and reachable on IPv6 Internet First 3 allowed bits are 001 in binary Global addresses could start with binary values 001 (2000::/3) through 111 (E000::/3) Exception: FF00::/8, reserved for multicasts Following 45 bits designate global routing prefix Next 16 bits designate subnet ID Last 64 bits identify individual network node continued

  14. IPv6 address types, continued Multicast Sends information or services to all interfaces that are defined as members of multicast group First 8 bits, FF = multicast address Anycast New, unique type of address in IPv6 Cross between unicast and multicast Identifies a group of interfaces Packets are delivered to the nearest interface as identified by the routing protocol’s distance measurement

  15. Subnet masks Used to identify network ID and host ID portions of IP address

  16. Network IDs Always contiguous and start on the left

  17. Default gateway Term for TCP/IP router Hosts use default gateway to deliver packets to remote networks Router Often a dedicated hardware device Sometimes computer with multiple NICs Supports IPv4, IPv6, or both Moves packets between networks Has an IP address for every network it’s attached to

  18. Routing example

  19. DHCP and DHCPv6 Dynamic Host Configuration Protocol Automated mechanism to assign IP addresses to clients Two versions Original DHCP used for IPv4 addressing DHCPv6 used for IPv6 addressing Can hand out IP addresses plus other TCP/IP configuration parameters

  20. Fully qualified domain names (FQDNs) Hierarchical naming scheme: Domain Name System (DNS) Berkeley Internet Name Domain (BIND) Three parts: Host name Domain name Top-level domain name Example: www.microsoft.com Subdomains allowed: server1.corporate.microsoft.com

  21. FQDN naming specifications RFC 1123: ASCII letters a through z (not case-sensitive) Numbers 0 through 9 Hyphens Maximum 255 characters Two nodes with same FQDN, except host name, don’t need to enter entire FQDN to connect

  22. Domain Name System (DNS) • Server with database matching host names to IP addresses • DNS name has three parts • Computer name • Domain name • Top-level domain name • Can also have subdomains to further divide

  23. NetBIOS 16-character name First 15 characters available for the name 16th character reserved to describe a particular service or functionality Can include: Letters Numbers ! @ # $ % ^ & ( ) - _ ' { } . ~ Must be unique continued

  24. NetBIOS, continued Can’t contain: Spaces \ * + = | : ; “ ? < > , Not case-sensitive 16th character reserved Expressed as hexadecimal In brackets <> Example: SUPERCORP<1C> SUPERCORP domain controllers Flat namespace

  25. Activity A-1 Examining addresses

  26. IPCONFIG • Use to retrieve a computer’s IP configuration • ipconfig /all • Display and modify the current TCP/IP stack • Can be used with switches • ipconfig /? • Examples: • ipconfig /release • ipconfig /renew

  27. Example of ipconfig /all results

  28. Activity A-2 Using IPCONFIG to view IP configuration

  29. Ping • Packet Internet Groper • Simple program to test IP connectivity between two computers • Uses ICMP packets • Syntax: ping computer • Where computer is the other computer’s name or IP address

  30. Successful ping

  31. Steps after unsuccessful ping • Use IP address of remote host instead • Ping a different computer • Use ipconfig to verify computer’s IP configuration • Verify configuration settings in Network window • Check physical connections • Reboot computer • Remove TCP/IP and reinstall

  32. Activity A-3 Testing TCP/IP connectivity

  33. TCP/IP architecture

  34. Activity A-4 Discussing the TCP/IP architecture

  35. Application-layer protocols Accept information from applications on the computer Send information to requested service provider Available only on TCP/IP networks Each Application-layer protocol is associated with a client application and service

  36. HTTP Hypertext Transfer Protocol TCP port 80 Most common protocol used on the Internet Used by Web browsers and Web servers Defines what commands Web browsers can send and how Web servers can respond Can use HTTP to upload information continued

  37. HTTP, continued Mechanisms for passing data: Common Gateway Interface (CGI) Internet Server Application Programmer Interface (ISAPI) Netscape Server Application Programmer Interface (NSAPI)

  38. HTTPS connections Secure Web servers use SSL (Secure Sockets Layer) or TLS (Transport Layer Security) TCP port 443 Create an encrypted communication channel Use https:// instead of http://

  39. FTP File Transfer Protocol TCP ports 20 (data) and 21 (control) Simple file-sharing protocol Includes commands for Uploading files Downloading files Requesting directory listings Transfers binary files over the Internet without encoding and decoding

  40. Trivial File Transfer Protocol Trivial FTP or TFTP UDP port 69 Has fewer commands than FTP Can be used only to send and receive files Can be used for multicasting

  41. Telnet Terminal emulation protocol TCP port 23 Used for remotely logging on to a networking device Specifies how Telnet server and Telnet clients communicate Supports only text-based interface

  42. Simple Mail Transfer Protocol SMTP TCP port 25 Used to send and receive e-mail between e-mail servers Also used by e-mail clients to send messages to the server Never used by clients to retrieve e-mail from server

  43. Post Office Protocol Version 3 (POP3) TCP port 110 Most common protocol for retrieving e-mail messages Has commands to download and delete messages from the mail server Doesn’t support sending messages

  44. Internet Message Access Protocol Version 4 (IMAP4) TCP port 143 Used to retrieve e-mail messages More features than POP3 Examples: Can choose which messages to download Allows for multiple folders for storing messages on the server side

  45. Transport-layer protocols Responsible for getting data ready to move across the network Two Transport-layer protocols: Transmission Control Protocol (TCP) User Datagram Protocol (UDP) TCP breaks messages down into smaller pieces called segments Identify applications by port numbers Combination of IP address and port number is called a socket

  46. Port numbers 16-bit integer, ranging from 0 to 65535 Three types: IP address + port number = socket

  47. Service port numbers

  48. Activity A-5 Using port numbers

  49. 802.1x standard Frequency band divisions Military Broadcasters Amateur radio operators Broadcast signal is a security issue IEEE 802.1x Port-based authentication framework for access to Ethernet networks Designed for wired Ethernet networks Applies to 802.11 WLANs continued

  50. 802.1x standard, continued Requires three roles in authentication process Device requesting access Authenticator Authentication server Allows multiple authentication algorithms Is an open standard

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