TCP/IP Overview and Components

TCP/IP Overview

• TCP/IP is a network protocol suite designed to deliver packets across networks of any size
• It's a suite of protocols handling tasks like logical addressing, address resolution, name resolution, dynamic address assignment, efficient packet delivery, and packet sequencing.

TCP/IP Components

• TCP/IP is the default protocol on Windows systems (IPv4 and IPv6).
• TCP/IP-related protocols include DNS, DHCP, TCP, UDP, IPv4, IPv6, ARP, ICMP, and ICMPv6.

TCP/IP Communication

• A DNS request is sent when a user opens a web page to resolve the website name into an IP address.
• The client determines if the target IP address is on the same network or a different one.

General Network Terms

• MAC address: the physical address for a network interface card (NIC)
• Frame: a formatted unit of data ready for the network medium
• Packet: the network layer data unit used in IPv4 and IPv6
• Segment: the transport layer data unit used by TCP and UDP

The Role of TCP and UDP

• TCP and UDP headers determine the destination application for data
• TCP and UDP use port numbers to identify source and destination application layer protocols
• IANA assigns port numbers to well-known network services

IPv4 Addresses

• IP addresses are 32-bit numbers divided into four 8-bit octets (0-255).
• Subnet masks (also 32-bit) determine network and host IDs.

IPv4 Addresses - Example

• 192.168.14.250 equals 11000000.10101000.0001110.11111010
• 255.255.255.0 equals 11111111.11111111.11111111.00000000

Binary Math

• Computers determine network IDs via a logical AND operation between the IP address and the subnet mask.
• 0 AND 0 = 0, 1 AND 0 = 0, 0 AND 1 = 0, 1 AND 1 = 1

IP Operation

• IP performs logical addressing, efficient packet delivery, and provides information necessary for packet routing.

Logical Addressing

• TCP/IP uses both logical (IP) and physical (MAC) addresses for communication.
• IP addresses primarily identify the network a computer is connected to.
• IP packets always include source and destination IP addresses.

Packet Routing

• Routing packets is a key IP responsibility
• Routers use destination IP addresses to determine the best path for delivery

IP Address Classes

• Classes A, B, and C are for hosts, with defined ranges for the first octet.
• Class A: First octet 1-127
• Class B: First octet 128-191
• Class C: First octet 192-223
• Class D: Reserved for multicasting (224-239)
• Class E: Reserved for experimental use (240-255)

Private IP Addresses

• Reserved IP addresses are for private networks unreachable directly via the internet
• Private classes: 10/8, 172.16/12, and 192.168/16

Private IP Addresses (cont'd)

• Link-local addresses (APIPA) are automatically assigned (169.254.1.0- 169.254.254.255)

Network Address Translation

• NAT enables organizations to utilize private IP addresses while connected to the internet.
• The NAT translates private addresses into public ones, allowing private networks to access the internet.

Classless Interdomain Routing (CIDR)

• CIDR uses IP addresses without default subnet masks
• Formatted as A.B.C.D/n, where n represents bits in the subnet mask

Broadcast Domains

• A broadcast domain defines devices that receive broadcast packets
• Broadcasts are packets addressed to all computers on a network.
• TCP/IP communication heavily relies on broadcast packets (DHCP, ARP)

Subnetting

• Subnetting re-allocates bits from the host portion to the network portion of an IP address, creating smaller address spaces
• Used to divide a large network into smaller subnetworks or conserve IP addresses
• Formula: 2^n, where n = number of bits re-allocated

Calculating a Subnet Mask

• Ensure sufficient host bits for assigning to computers on each subnet
• Use the formula 2^n - 2, with n representing the host bit count in the subnet mask.

A Pattern Emerges (Table 2)

• Shows subnetwork numbers and addresses in binary.

Determining Host Addresses (Table 3)

• Provides the range of valid host addresses for each subnet in binary and decimal.

Another Subnet Mask Example (Figure 3)

• Illustrates how different subnets can exist within a larger network

Supernetting

• Supernetting aggregates smaller subnets for streamlined routing tables.
• Reallocates network ID portion of an IP address to accommodate a larger supernet

Configuring IPv4 Addresses

• Every IP configuration must include a subnet mask
• All hosts on the same physical network must have the same network ID
• Host IDs must be unique within any given network
• An IP address cannot have all host ID bits as 0 and 1

Configuring Multiple IP Addresses

• Windows allows multiple IP addresses per network connection
• Multi-address configuration is useful for computers hosting services accessible through different addresses

Configuring the Default Gateway

• Almost all IP configurations use a default gateway
• Its address must match the host's network ID.
• Multiple gateways are possible

Using Multihomed Servers

• Multihomed servers have multiple NICs each attached to a distinct IP network
• Provides access to internal and external users
• Serves as a router or VPN server

Using the route Command

• Windows computers maintain a routing table indicating packet destinations
• route print displays the table sorted in 5 columns (Network Destination, Netmask, Gateway, Interface, Metric)

IP Configuration Command-Line Tools

• netsh, PowerShell cmdlets, ipconfig, ping, arp, tracert, nslookup are used to manage IP configurations and verify connectivity.

Using netsh

• netsh.exe is a command-line utility for displaying or modifying network configurations

Using PowerShell Cmdlets

• PowerShell cmdlets allow for viewing and modifying IP settings.
  • Get-NetIPConfiguration for network interface information.
  • Get-NetIPAddress for detailed IP address configuration.
  • Set-NetIPInterface for configuring DHCP client, "wake on LAN", and router settings.
  • Set-DnsClientServerAddress for setting DNS server addresses for the DNS client.

Using ipconfig

• Used primarily (but not exclusively) to display IP address settings.
• Available options include /all, /release, /renew, /displaydns, /flushdns, and /registerdns.

Using ping

• Used to check connectivity between two computers by sending ICMP echo request packets
• /? displays options for pings.

Using arp

• Displays and modifies the ARP cache, listing IP addresses and corresponding MAC addresses.
• Has options for displaying (-a, -g), deleting entries (-d) and adding static ARP entries (-s).

Using tracert

• Displays the route packets take between computers
• Starts with a TTL of 1, increasing until the destination computer is reached.
• Useful for diagnosing and troubleshooting routing topologies.

Using nslookup

• Employed in interactive and command mode to check for and debug DNS operations
• Typing host in interactive mode displays the host's address.

IPv6 Overview

• IPv4's address space is limited which has driven the development of IPv6
• IPv6 addresses are fundamentally different than IPv4 addresses in their format and design

IPv6 Address Structure

• IPv6 addresses employ 128 bits (in contrast to IPv4's 32 bits).
• Hexadecimal representation with colons separating 16-bit segments.

Transitioning from IPv4 to IPv6

• Dual IP layer design allows for concurrent IPv4 and IPv6 functionalities
• Related methodologies include IPv6-over-IPv4 tunneling, ISATAP, and 6to4, for seamless transition.

Dual IP Layer Architecture

• Dual IP architecture enables direct communication between IPv4 and IPv6 devices using native packet types.
• Tunneling is also possible to adapt IPv6 packets to IPv4-based network environments

IPv6-over-IPv4 Tunneling

• A network protocol that facilitates the transmission of non-compatible packets by encapsulating them in compatible headers.

Intra-Site Automatic Tunnel Addressing Protocol (ISATAP)

• Protocol that facilitates IPv6 networking across an IPv4 network using dual IP layer hosts.

6to4 Tunneling

• An automatic IPv6-over-IPv4 tunneling protocol that enables connectivity, primarily between routers.

Teredo tunneling

• An automatic IPv6-over-IPv4 protocol which solves the issue that hosts may not have a public IP address for 6to4, and is able to traverse firewalls.

Summary of important topics

• TCP/IP overview, components, and communication details
• IPv4 addressing, binary math, subnetting, IP classes, reserved addresses, private IPs, and NAT
• IPv6 overview, address structure, transition methods to IPv6 (dual IP layer architecture, IPv6-over-IPv4 tunneling,ISATAP, 6to4, Teredo)
• Important command-line tools (netsh, PowerShell, ipconfig, ping, arp, tracert, nslookup) for IP configuration and diagnostics.

Explore the TCP/IP protocol suite, which is essential for delivering network packets across various networks. This quiz covers the fundamental components of TCP/IP, communication processes, general network terms, and more, providing a comprehensive understanding of how networks operate.