Cisco Packet Tracer Commands

Cisco Packet Tracer

• ping: Verifies communication between two PCs or if you can reach the server.
• ipconfig: Configures IP and communicates current IP address.
• enable: Activates privileged mode.
• ?: In privileged mode, displays all possible commands.
• reload: Resets settings to original state but can save changes if needed, such as hostname modifications.
• config t: Enters global configuration, allowing changes to hostname, a global setting.
• hostname: Changes the hostname of the device,
• copy running-config startup-config: Saves all configurations made; can also be done as copy run start.
• enable password / enable secret: Sets a password to access privileged mode.
• enable password is typically visible with show running-config.
• enable secret encrypts the password, hiding it with random characters.
• line console 0: Enters console line configuration to set a password using password ***, applied with login for "User Access Authentication".
• banner motd (message of the day): Displays a message each time someone logs into the console.

Network Components

• A host is any device that connects to the network and participates in data transmission.

Host Types

• Host Server: Provides services to other hosts, manages requests, and responds with data or resources, e.g., web server, mail server, database server in a client-server network.
• File Server:
  • Manages and stores files for sharing between users and devices.
  • Enables remote file access and manages permissions.
• Web Server:
  • Hosts websites and handles HTTP requests from clients.
  • Returns web pages and multimedia content to users.
• Email Server:
  • Manages sending, receiving, and archiving emails,
  • Facilitates email communication between users and domains.
• Host Client:
  • Utilizes services provided by host servers.
  • Examples include computers, smartphones, and tablets.
  • Sends requests to servers to access specific content or services.

Peer-to-Peer Networks

• Peer-to-peer networks have hosts acting as both clients and servers.
• Each device can directly share resources and data with others.

End Devices and Intermediate Devices

• End Devices:
  • End devices are the origin or destination of a message on the network, including computers, smartphones, and tablets.
• Intermediate Devices:
  • Intermediate devices connect end devices, including routers, switches, hubs, and modems.
  • Crucial for ensuring efficient data transmission.
• End devices initiate communication, such as a computer or smartphone.
• Intermediate devices facilitate data flow, ensuring information reaches its destination correctly and promptly.

Network Support

• Network support: The method of transporting information from source to destination.
• Metallic wires in cables: Encode data as electrical pulses. (copper or other metals)
• Glass or plastic fibers (fiber optic cable): Encode data as light pulses, e.g., in glass cables.
• Wireless transmission: Data is encoded via modulation of specific electromagnetic wave frequencies (the air or "ether").

Network Representations

• Network Interface Card (NIC): Physically connects the end device to the network; communication is impossible without it.
• Interface: Specialized ports on network devices that enable connections to individual networks.
• Physical Port: The connector on a switch where cables are physically connected:
  • Physical port is a generic term for any connector on a connectivity device.
  • Interface is a specialized port for network connection, found mainly on network devices like routers or switches.

Topology Diagrams

• Topology diagrams:
  • Required documentation for anyone working with networks.
• Physical topology diagrams: Illustrate the physical location of intermediate devices and cable installation.
• Logical topology diagrams: Illustrate ports with their IP addresses and devices.

Types of Common Networks

• Network Classification: Networks are divided by size and type.
• BAN (Body Area Network):
  • Small network, typically wearable like Bluetooth headphones.
• PAN (Personal Area Network):
  • Covers a desk or small area, with devices like smartphones and computers.
• LAN (Local Area Network):
  • Covers a building or adjacent buildings, such as offices or schools.
• MAN (Metropolitan Area Network):
  • Covers a city or metropolitan area by connecting multiple LANs.
• WAN (Wide Area Network):
  • Extends over states or regions.

WAN characteristics

• WANs interconnect LANs across large geographic areas, cities, states, provinces, countries, or continents.
• WANs are generally managed by multiple service providers.
• WANs typically provide lower speed connections between LANs.
• GAN (Global Area Network): Global network covering the entire globe, like the Internet.
• LANs connect creating a vast network.
• Intranet is a private LAN and WAN connection within an organization.
• Extranet is used by organizations to provide secure access to specific data for external collaborators like suppliers or clients.

Internet Connections

• Internet Connections for Home and Small Offices:
  • Cabling: Uses TV cables, fast and reliable, with high bandwidth, common in cities.
  • DSL: Uses telephone lines, always active, faster downloads than uploads, ideal for home offices.
  • Cellular: Mobile networks (3G/4G/5G), signal-dependent, with performance limited by the network.
  • Satellite: Ideal for remote areas, but slow with latency, requires a direct line of sight to the satellite.
  • Dial-up: Economical but slow, uses telephone lines, and doesn't support simultaneous phone and internet use.
  • Fiber optic: Very high speed, advanced and stable technology, perfect for large data transfers.

Business Internet Connections

• Dedicated Leased Line: Reserved circuits connecting distant offices, creating private networks for data or voice, rented monthly or annually.
• Metro Ethernet: Extends LAN technology to WAN, using Ethernet to connect larger areas.
• Business DSL: Available in various forms like SDSL (Symmetric DSL), which offers equal upload and download speeds, ideal for businesses.
• Satellite: Provides internet connection where cabling solutions are unavailable, useful in remote areas.
• Converged Networks:
  • Unlike dedicated networks, handle data, voice, and video across many types of devices on the same network infrastructure.
• Traditional Separate Networks:
  • Each network used different technologies to transport signals, with their own rules and standards for successful communication.
  • Resulted in more services being run on more networks.
• IOS (Internetwork Operating System):
  • Command-line interface operating system for network devices.
  • Configuration is done via a console, a serial communication port through a console cable.

Reliable Networks

• Network Architecture:
  • Fault Tolerance: The ability of a device to function even when there are failures.
  • Some companies need devices running 24/7.
  • Redundancy means incorporating backup components or systems to ensure uninterrupted system operation.
• SPOF (Single Point of Failure): A single point of vulnerability whose malfunction can lead to anomalies or the cessation of service.
• Scalability: Server's ability to manage an increasing number of data requests without compromising performance.
• Improves with adaptable system to maintain smooth and fast operation.
• Quality of Service (QoS): Manages network congestion and ensures reliable content distribution.
• Prioritizes critical traffic and video streams.
• Securing the network: Network security protects transmitted and stored information, ensuring: Confidentiality, Integrity, Availability.

Security mechanism

• Authentication: Verifies the identity of users or devices.
• Authorization: Grants permissions for resource access based on authenticated identity.

IP Address

• IP Address: A unique identifier assigned to a network host for precise location.
• It consists of 4 bytes separated by periods, with numbers in decimal format.
• The minimum value that can be configured is 0, while the maximum value is 255.
• Example: 192.168.10.14 An IP address is composed of two parts:
  • Identifies the host's location within the network.
  • Host specific IP address
• When the value is 255, it refers to the Network ID, while the value 0 corresponds to the Host ID.
• The subnet mask (e.g., 255.255.255.0) defines the network structure and the allocation of IP addresses.

Network Trends

• BYOD (Bring Your Own Device):
  • Bringing personal devices onto a network can pose risks, such as introducing viruses.
• Cloud Computing:
  • Allows storing data and using online applications instead of doing so locally.
  • Offers businesses scalable IT capacity without new infrastructure, staff, or software.
  • Data is stored in distributed data centers, which ensure security and reliability.
  • Small businesses often rent space in these data centers, reducing costs.
  • Four types of cloud: public, private, hybrid, and community.
• Powerline and Wireless Broadband Networks:
  • Powerline Network: Uses existing electrical wiring for data transmission, creating an internet network via power sockets. Powerline adapters connect to sockets and devices to extend the network.
  • Wireless Broadband: Uses radio waves, such as Wi-Fi, for high-speed internet access without cables.

Network Security

• Security Threats:
  • Virus, worm, and Trojan: Malicious software and arbitrary code running on a user's device.
  • Spyware and adware: Software installed on a user's device that secretly collects information.
  • Zero-day attacks: Attacks that occur on the first day a vulnerability is known.
  • Threat actor attacks user devices or network resources maliciously.
  • Denial of service attacks: Attacks designed to slow down or block applications and processes on a network device.
  • Interception and data theft: An attack to acquire private information from a company's network.
  • Identity theft: An attack to steal user credentials to access private data.

Security Solutions

• Antivirus and antispyware:
  • Protect devices from harmful software like viruses, malware, and spyware.
  • Detect, block, and remove threats to ensure data and system security.
• Firewall Filtering:
  • Blocks unauthorized access to the network, both inbound and outbound.
  • Can be implemented via a host-based firewall or on a domestic router.
• Dedicated Firewall Systems:
  • Provide advanced features, filtering large amounts of traffic more precisely.
  • It can be used in corporate environments for robust and scalable protection.
• Access Control Lists (ACL):
  • Tools to filter and manage network access.
  • Used to determine which users or devices can communicate with certain services or resources.
• Intrusion Prevention Systems (IPS):
  • Detect and respond to fast-moving threats like zero-day or zero-hour attacks.
  • Identify suspicious activity and intrusion attempts, blocking them before they can damage the network or system.
• Virtual Private Networks (VPN):
  • Create a secure connection between a user's device and the corporate network or the internet.
  • Protect the privacy and security of remote workers by encrypting traffic to prevent interception.