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: EIGRP Automatic Summarization

This hands-on lab enables EIGRP's legacy automatic summarization feature on a router with discontiguous subnets, observing the routing problem it creates, then disables it to restore correct connectivity.

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Hands-On Lab: Passive Interfaces for EIGRP Updates

This hands-on lab configures a passive interface in EIGRP to stop routing updates from being sent out a LAN-facing interface while the network remains advertised, mirroring the same security and efficiency rationale covered earlier for OSPF passive interfaces.

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Hands-On Lab: Summarizing Routes with EIGRP

This hands-on lab manually configures interface-level route summarization in EIGRP, advertising a single aggregated route instead of several specific subnets, and verifies the automatically created Null0 discard route that prevents summarization-related loops.

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Hands-On Lab: Verifying the EIGRP Database

This hands-on lab examines the EIGRP topology table directly, identifying the successor and feasible successor for a destination network, and demonstrates how this underlying data explains what appears in the IP routing table.

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Hands-On Lab: Implementing HSRP

This hands-on lab configures HSRP between two routers sharing a virtual gateway address, sets priority and preempt to control which router is active, and verifies automatic failover when the active router fails.

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Hands-On Lab: Configure GLBP Redundancy

This hands-on lab configures GLBP between two routers to achieve load balancing across both routers simultaneously, verifying that different hosts receive different virtual MAC addresses and therefore route through different physical gateways.

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Hands-On Lab: Configuring VRRP

This hands-on lab configures VRRP between two routers as the open-standard alternative to HSRP, using a real interface address as the virtual IP, and verifies Master/Backup roles and automatic failover behavior.

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Hands-On Lab: Configuring Standard Numbered ACLs

This hands-on lab configures a standard numbered ACL to permit traffic from a specific subnet while denying everything else, applies it to the correct interface and direction, and verifies both permitted and denied traffic behave as expected.

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Hands-On Lab: Configuring Extended Numbered ACLs

This hands-on lab configures an extended numbered ACL to permit only specific traffic types by source, destination, protocol, and port, applying it close to the source and verifying granular filtering that a standard ACL could never achieve.

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Hands-On Lab: Configuring Named ACLs

This hands-on lab configures a named extended ACL, demonstrating how a descriptive name replaces a numeric identifier and how individual entries can be edited by sequence number without recreating the entire list.

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Hands-On Lab: Using ACLs to Restrict VTY Access

This hands-on lab configures a standard ACL applied specifically to a router's VTY lines to restrict remote management access to a single trusted management subnet, verifying both permitted and blocked SSH connection attempts.

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Hands-On Lab: Configuring Static NAT

This hands-on lab configures static NAT to provide a consistent, permanent public IP address for an internal server, verifying inbound connections from the internet reach the server correctly through the translated address.

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