Computer Networks

Computer Networks

Infrastructure, Systems, and Connectivity

Network ProtocolsCommunication InfrastructureOperating Systems and Server ManagementNetwork Security and EncryptionCloud Computing and Virtualization

Articles in this Section

Hands-On Lab: PPP Authentication Using PAP

This hands-on lab configures PAP authentication on a PPP serial link, demonstrating the simple two-way username and password exchange PAP uses, and shows what happens when the configured credentials do not match between the two routers.

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Hands-On Lab: PPP Authentication Using CHAP (Method 1 — Matching Usernames)

This hands-on lab configures CHAP authentication on a PPP serial link using matching local usernames on both routers, demonstrating CHAP's more secure challenge-response exchange compared to PAP and highlighting the critical requirement that both sides share an identical secret.

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Hands-On Lab: PPP Authentication Using CHAP (Method 2 — ppp chap hostname/password)

This hands-on lab configures CHAP authentication using the alternative ppp chap hostname and ppp chap password interface commands rather than matching local usernames, a method that scales far better when a single router has many WAN links to different peers.

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Hands-On Lab: Configuring eBGP Between Two Autonomous Systems

This hands-on lab configures a basic eBGP peering session between two routers in different autonomous systems, advertises a network into BGP, and verifies the resulting route appears correctly in the neighboring router's routing table.

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Hands-On Lab: Configuring GRE Point-to-Point Tunnels

This hands-on lab configures a GRE tunnel between two routers across an intermediate transit network, allowing routing protocols and multicast traffic to pass between sites even when the underlying transport network would not normally support them directly.

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Hands-On Lab: Power over Ethernet (PoE) Basics

This hands-on lab covers verifying PoE capability on a switch port, checking how much power is being drawn by a connected device such as an IP phone or access point, and configuring power priority to protect critical devices during a power budget shortage.

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Hands-On Lab: Verifying IP Parameters on Windows (GUI and CLI)

This hands-on lab covers checking a Windows PC's current IP configuration using both the graphical Network Connections interface and the command-line ipconfig utility, including releasing and renewing a DHCP-assigned address.

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Hands-On Lab: Verifying IP Parameters on Linux (GUI and CLI)

This hands-on lab covers checking a Linux machine's current IP configuration using both the GUI network settings panel and command-line tools, and demonstrates renewing a DHCP lease using standard Linux networking utilities.

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Hands-On Lab: Verifying IP Parameters on macOS (GUI)

This hands-on lab covers checking a Mac's current IP configuration using the System Settings network panel, viewing detailed TCP/IP information, and renewing a DHCP lease directly from the graphical interface.

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Hands-On Lab: Configuring Standard VLANs on Catalyst Switches

This hands-on lab covers creating standard-range VLANs, assigning access ports to them, and verifying that devices in different VLANs are properly isolated from each other at Layer 2.

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Hands-On Lab: Configuring VTP Clients and Servers on Catalyst Switches

This hands-on lab configures VLAN Trunking Protocol between a server switch and a client switch, demonstrating how VLANs created on the server automatically propagate to the client without manual configuration on every device.

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