1. Private IP addresses
    • 10.
    • 172.16.
    • 192.168.
  2. TCP/IP Design goals:
    • Hardware, software independence
    • Built-in failure recovery
    • Reliable service even with high error rates
    • Efficiency; low data overhead
    • Allow adding new networks without service disruption
  3. Benefits of TCP/IP
    • Open standard; hardware/software- independent
    • Operating system-independent
    • Separated from underlying hardware
    • A routable protocol
    • Includes reliable, efficient data-delivery mechanisms
    • Uses common addressing scheme
  4. Describe IP
    • Internet Protocol operates at the Network layer of the OSI model
    • Routes data to destination
    • Connectionless (best effort transmission)
  5. IP header includes:
    • Source and destination address
    • Protocol number
    • Checksum
    • Code representing the enclosed higher-layer protocol
    • TTL (Time to Live) field: Contains hop count
  6. Describe TCP
    • Ensures reliable, verifiable data exchange
    • Provides connection-oriented transmission
  7. TCP header Includes:
    • Source and destination port numbers
    • Datagram sequence number
    • Control bit flag indicating how the segment should be handled
    • Checksum
    • Window
    • Urgent Pointer
    • Enables fragmented datagrams and their reassembly.
    • -Sequence number
    • -Fragmentation offset value
  8. Key features of TCP communication
    • Flow control(flows at slower speed of 2 devices)
    • Acknowledgment(ACK, NAK)
    • Sequencing(put packets in proper order)
    • Checksums(error control)
    • Retransmission of lost segment
  9. Describe an IPv4 address
    • 32-bit number represented as a four-part decimal number.
    • Often called dotted-decimal notation
    • Each byte (octet) can have decimal value of 0 – 255
    • Two portions: Network identifier+Host identifier
  10. What the default subnet masks for class A, B, C?
    • A
    • B
    • C
  11. How are the two portions of an IPv4 address identified?
    • Network portion then host portion
    • all 1's for network portion followed by all 0's for host portion
  12. ICANN
    • Internet Corporation for Assigned Names and Numbers (ICANN)
    • Registers, maintains IP addresses
    • Registered IP addresses only required for connecting to Internet
    • not private IP addresses
  13. How are private ip address different from none-private?
    • Not recognized by Internet routers
    • Require Network Address Translation (NAT), proxy servers to replace them with valid Internet address
    • Used inside corporate networks (reduces demand for IPv4 Addresses)
  14. What is NAT?
    • Network Address Translation
    • Is the process where transmissions can be routed appropriately from an outside system to internal systems with private IP addresses
    • Makes it possible to hide the internal IP addresses from external systems
    • Is built into most routers and firewalls
  15. Internet Proxy Servers:
    • Act as intermediaries between systems
    • Check and validate incoming requests to see if it can fulfill the request before passing it on to the server
  16. Class A:
    • Designed for very large networks only
    • 0,7bits network, 24bits host
    •– ( /8)
    • First octet value of 126 or less
    • A first octet value of exactly 127 indicates a software loopback test address
  17. Class B:
    • Designed for medium-sized networks
    • 10+14bits network + 16bits host
    •– (172.16 .0.0/16)
    • First octet value of 128 through 191
  18. Class C:
    • Designed for smaller networks
    • 110+21bits network + 8bits host
    •– ( /24)
    • First octet value of 192 through 223
  19. Class D:
    • Multicast address range; cannot be used for networks
    • 1110+28bits
    • First octet value of 224 through 239
  20. Class E:
    • Reserved for experimental purposes
    • 1111+28bits
    • First octet value greater than 239
  21. IP subnet:
    • Uses host address bits as additional network bits, creating additional networks.
    • Can be routed independently, allowing a much better use of address space and bandwidth
  22. Subnetting Advantages:
    • Minimizes network traffic
    • Isolates networks from one another
    • Improves performance
    • Defines limits of a broadcast domain
    • Optimizes use of IP address space
    • Enhances the ability to secure a network
  23. What are the address portions for specific computer with ip and subnet mask
    • 142 is class B so default subnet is
    • network is 142.155
    • subnet is 40
    • host is 100
  24. CIDR
    • Classless Interdomain Routing (CIDR)
    • CIDR is an alternative to representing addresses as an IP address or subnet mask
    • Described as “slash x (/x)” networks
    • X represents number of bits in the IP address range used as the network address
    • With CIDR, Class C network becomes a /24
    • Reduces routing table size
    • Used to define networks that fall between old classifications
    • /21 subnet mask:
  25. Private Addresses Benefits:
    • Network set up without registering addresses
    • Boundary between network and Internet
    • Prevents hosts on the Internet from knowing the internal addressing scheme of the network
    • (Used for setting up network with public addresses used as connections to Internet)
  26. port number (port address):
    • applications associated with data
    • source port for the source application
    • destination port for the destination application
    • Range 0 – 65535
    • Windows: \windows\system32\drivers\etc
    • Two types of ports: UDP ports, TCP ports
    • Each port is assigned a unique 16-bit number
  27. socket
    • A socket is a combination of IP address, associated protocol, and port number
    • Identifies a single network process
    • Two sockets required for connection-oriented protocols
  28. IPv6 uses:
    • 128-bit addressing scheme
    • 8 sets of 4 hexadecimal digits
    • 3FFE:0B00:0800:0002:0000:0000:0000:000C
    • May be abbreviated (drop leading 0s, single groupings of 0s)
    • 3FFE:0B00:0800:0002::000C
    • Each host has three addresses:
    • -Host ID, Network ID, Routing information
  29. FQDN
    Fully Qualified Domain Name (FQDN) consists of a host name and a domain name
  30. Name resolution:
    • Finding IP address of domain name.
    • Resolution methods include:
    • HOSTS file
    • Domain Name System (DNS)
    • Windows Internet Naming Service (WINS)
  31. Top-level domains:
    • .com: commercial organization
    • .edu: educational establishment
    • .gov: branch of the U.S. government
    • .int: international organization
    • .mil: branch of the U.S. military
    • .net: network organization
    • .org: nonprofit organization
    • Plus many more
    • ICANN: Assigns Internet domain names
  32. DNS
    • Translates host names, domain names to IP addresses
    • Uses zone file (DNS table):
    • Updated manually, or automatically in dynamic DNSs
  33. DHCP
    • Dynamic Host Configuration Protocol (DHCP): Centralizes management of IP addresses
    • DHCP scopes: pools of IP addresses assigned for leasing to clients
    • Four messages:
    • APIPA (Automatic Private IP Addressing): Can enable host to use when no address received from DHCP server
  34. Most commonly used utilities
    • ping
    • pathping
    • tracert (traceroute)
    • ipconfig (ifconfig)
    • nslookup (dig)
  35. ping:
    • Tests communication between two hosts
    • Reports host response and round-trip time
  36. pathping:
    Returns information about routers in path
  37. tracert:
    • Route information
    • tracert on Windows, MS-DOS
    • traceroute on Unix, Linux
  38. ipconfig, ifconfig
    • Report IP configuration information
    • Manage automatic IP address configuration
    • ipconfig: Windows
    • -ipconfig
    • -ipconfig /all
    • -ipconfig /release
    • -ipconfig /renew
    • ifconfig: Unix, Linux
  39. Nslookup, Dig
    • Used for troubleshooting DNS servers
    • -Returns hostname and IP address of default DNS server.
    • -Tests DNS server operations
    • -View and set DNS server options
    • nslookup: Windows NT and later, Unix, Linux
    • dig: Unix, Linux
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