In this section, we explore the world of programming, algorithms, networks, and infrastructure
This hands-on lab configures EIGRP using precise wildcard masks in the network command to advertise only specific subnets rather than entire classful networks, giving finer control over exactly which interfaces participate in EIGRP.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
