Cisco Troubleshooting Labs For CCNA, CCNP, and CCIE Students

Explore a four-router, three-switch Cisco topology with VLANs 10 and 20, a layer-3 default gateway, and tickets showing routers cannot ping each other.

Configure vlan 10 on switch 1 and switch 2, set trunk encapsulation to dot1Q, resolve inconsistent ports, and restore connectivity between router 1 and router 2 via successful ping.

Troubleshoot inter‑VLAN routing by creating VLAN 20 on switch 2, enabling the VLAN interface, assigning Ethernet 0/3 to VLAN 20, and confirming connectivity with show commands and a ping.

Troubleshoot the router-to-router connectivity by correcting trunk configurations, disabling bpdu guard on switch 3’s ethernet 0/1, creating vlan 10, and verifying ping success from router 1 to router 4.

Master switching lab 2 topology and tickets, identical to lab 1, by diagnosing router ping failures and using only show commands on switch two.

Create VLAN 10 on switch 1, assign Ethernet 0/1 to VLAN 10, propagate VLAN 10 to switch 2 with VTP Cisco, and adjust switch 1 priority to resolve root guard.

Troubleshoot connectivity between router 1 and router 3 by creating vlan 20 on switch 1, propagating it with vtp, resolving root guard blocking, and confirming a successful ping.

Troubleshoot router connectivity by turning switch 3 port into trunk, configure trunk allowed VLANs, and synchronize VTP domain to enable VLAN 10; verify with cross-router pings.

Repair the six-router topology with EIGRP and OSPF areas so every loopback can ping every other loopback, using a TCL script to ping each loopback thrice for 100% success.

Correct the EIGRP k-value mismatch between router 1 and router 2 by restoring the default metric weights. Reestablish neighborship and verify connectivity by pinging 2.2.2.2 from Router 1's loopback.

Troubleshoot the EIGRP connectivity between router 2 and router 3 loopbacks, fix misaligned hello behavior, and configure matching neighbor statements to restore ping to 3.3.3.3.

Troubleshoot OSPF adjacency between router 3 and router four by aligning hello and dead timer values on Ethernet 0/1 and 0/0, then verify connectivity with a loopback ping.

Diagnose and fix OSPF adjacency between router four and router six by correcting the network command and enabling OSPF on the S1/0 interface. Enable frame-relay broadcast and verify loopback route.

Troubleshoot OSPF adjacency and stub area configurations across routers, ensure the DR is correctly elected, and verify full connectivity with a TCL script and ping tests across the frame-relay network.

Practice routing troubleshooting in lab 2 using the same topology, base configuration, and tickets as lab 1, with the new restriction of not using the neighbor command.

Resolve router 1 to router 2 connectivity by correcting the EIGRP network command and IP addressing, enabling EIGRP on interfaces, and advertising the loopback for a successful ping.

Troubleshoot a routing adjacency between router 2 and router 3 by inspecting EIGRP neighbors and an inbound acl that denied eigrp; remove the acl to restore the loopback ping.

Correct router four's OSPF area from 1 to 0 to establish adjacency with router 3, then ping 4.4.4.4 succeeds.

Diagnoses an OSPF adjacency issue between router four and router six, fixes non-broadcast network type by applying broadcast, and corrects a mismatched authentication key to restore adjacency and successful ping.

Diagnose and resolve OSPF adjacency and loopback connectivity issues among routers, fixing mismatched key, duplicate router ID, and discontiguous area problems, then validate full connectivity with a TCL script.

Explore routing lab 3 topology with the same base configuration and tickets as labs 1 and 2, while enforcing the restriction not to change the OSPF network type.

Investigate and fix router 1 to router 2 loopback connectivity by correcting the eigrp autonomous system mismatch to 10, aligning vlans, and adjusting an acl, then verify adjacency and ping.

Troubleshoot eigrp adjacency between router 2 and router 3 by correcting router 3's network address for the loopback and enabling eigrp on the correct ethernet interface, then verify ping succeeds.

Troubleshoot router 3 and router 4 loopback connectivity by redistributing EIGRP into OSPF with the subnets keyword, correcting classful/classless mismatches, and achieving successful ping to 4.4.4.4.

Diagnose a loopback connectivity issue between router four and router six by adjusting OSPF adjacency and unicast neighbor settings to enable a successful ping.

Resolve loopback connectivity between router four and router seven by configuring non-broadcast OSPF neighbors with unicast hellos and simple authentication. Confirm full connectivity with a TCL script and cross-router pings.

Routing lab four uses same topology and base configuration as labs one to three, with tickets and requirements; do not add to frame relay configuration; you may change or replace.

Resolve router loopback connectivity by enabling eigrp on Ethernet 0/0, removing the passive interface, and fixing key chain whitespace to restore adjacency and successful ping.

Troubleshoot eigrp neighborship between router 2 and router 3 by correcting md5 authentication key chain name, enabling proper authentication on interfaces, and verify loopback reachability.

Fix OSPF exstart adjacency caused by a MTU mismatch between router 3 and router 4. Change the MTU to 1500 on the affected interface and ping the loopback to verify.

Fix OSPF adjacency between router four and router six by aligning authentication types and areas, removing wrong frame-relay map, and using 100.4; verify with ospf adjacency debug and loopback ping.

We troubleshoot connectivity between routers four and seven by fixing OSPF authentication mismatch, DR issues, and next-hop frame-relay problems, then resolve redistribution and area advertising to achieve full loopback connectivity.

Navigate a four-lab BGP topology with three routers, OSPF and EIGRP interconnections, and a ticket-driven loopback ping repair from loopback 11 to loopback 33 under strict configuration restrictions.

Diagnose a BGP neighborship issue between loopback 11 on router 1 and loopback 33 on router 3, fix address and update-source mismatches, and resolve a race condition to restore connectivity.

Fix the BGP neighborship by correcting router 1's neighbor IP, clearing updates, enabling next-hop-self, and advertising loopback 11 via OSPF so router 3 learns it and ping succeeds.

Troubleshoot BGP across three routers by correcting router 1's AS, adjusting router 2's maxas limit, and removing an AS-path prepend on router 3, enabling loopback 11 to reach 33.

Diagnose and fix an eBGP multi-hop issue between loopbacks, adjust next-hop and route maps, and ensure the 33 network is advertised and reachable.

Explore an IPv6 labs topology with four routers, a layer 3 switch, and a frame relay switch, using OSPFv3 for IPv6 while router 2 remains IPv4 only, with tunnel 13.

Troubleshoot IPv6 connectivity between router 1 and router 4 by verifying interface statuses, enabling IPv6 and OSPFv3, correcting tunnel source/destination, advertising loopback, and fixing frame-relay maps to establish adjacency.

Troubleshoot IPv6 connectivity across a GRE tunnel and OSPFv3 adjacency, identify protocol mismatches and access-list blocks, and restore routing by aligning tunnel mode and advertising loopback addresses.

Explore the ip services lab topology with four routers, grb protocol with as 1, nat on router 2, and dhcp on router 3 across 12, 23, and 34 networks.

Resolve a router failover issue by aligning MD5 authentication on both sides and enabling preemption so router 2 remains the active router on interface Ethernet 0/0.

Troubleshoot ntv synchronization on router 2 by diagnosing dhcp relay, dhcp snooping, and interface configuration to obtain an ip from router 3 and advertise loopback in EIGRP to align clock.

Diagnose a connectivity issue between router one and Proctor by tracing routes and inspecting router two's NAT configuration, then correct the inside/outside interface mapping and confirm connectivity with NAT translations.

Review the ip services lab 2 topology, mirroring lab 1, with the dhcp server set to router four instead of router three, while maintaining the same base configuration and tickets.

Configure hsrp groups to make router 2 the active for group 1, remove group 2 misconfigurations, set the virtual ip address for group 1, and enable preemption.

Troubleshoot NTP in a Cisco network by resolving unsynchronized clocks between routers, correcting DHCP/IP helper configurations, and aligning authentication keys to achieve synchronized time.

Trace and fix a NAT/ACL misconfiguration in an IP services lab by correcting access-list 1 to permit 192.168.12.0/24, restoring NAT translations, and enabling ping between router 1 and router 2.