Curriculum topic
Troubleshooting
FullA structured method for isolating a fault, and reading the shape of a problem from the symptoms it produces.
- lesson
- 6 lessons
- quiz
- 9 quizzes
- question
- 19 questions
- lab
- 24 labs
Taught, assessed and practised in a lab.
Why this matters
Network+ weights troubleshooting more heavily than any other domain, and it is the one skill that does not transfer from reading alone - it needs a broken network to practise on.
Further reading
Technical guides
Learn
Modules covering this topic
6 lessons on this topic, sequenced inside these modules alongside their quizzes and labs.
- Diagnosis in practiceNetwork operations and design
- Direction and stateNetwork security and acls
- Filtering by addressNetwork security and acls
- Dhcp in operationNetwork services
- Services assessmentNetwork services
- Network basicsNetworking fundamentals
- Network servicesNetworking fundamentals
- Switching and vlansNetworking fundamentals
- BgpRouting protocols
- Choosing a pathRouting protocols
- EigrpRouting protocols
- Knowing what is plugged inRouting protocols
- Ospf areas and faultsRouting protocols
- Static routing faultsRouting protocols
- When the link is the problemRouting protocols
Practice
Hands-on labs
Real virtual networks with device consoles, graded automatically. Addressing is regenerated on every attempt.
- Egress Filter on the Records Server
- The Firewall That Never Saw the Request
- Traffic Leaves by the Backup Circuit
- eBGP Session Up, No Routes
- Slow, Not Broken
- DHCP Scope Eats the Server Block
- DHCP Hands Out the Wrong Gateway
- EIGRP - Fix R2 (3-Router Chain)
- Static Route Outranks OSPF
- iBGP Route Learned but Never Installed
- Interface Administratively Down
- The Patch Panel Labels Are Wrong
- Small Packets Fine, Large Packets Gone
- OSPF Area Mismatch on a New Link
- OSPF Stuck in ExStart
- The Protocol That Loses Your Subnet Masks
- Shared-Segment Wrong Next-Hop
- Overbroad Summary Route Blackhole
- One Server, Wrong Exit Interface
- The Route That Isn't There
- Tagged Port, Untagged Host
- Trunk Missing a VLAN
- Access Port in the Wrong VLAN
- Allow Access to Wiki Replica
Assess
Graded quizzes
19 graded questions across 9 quizzes, taken inside the modules above. Wrong answers explain the specific misconception behind the option you chose.
Review
Spaced repetition
Troubleshooting is tracked on the review ladder. Once you have answered a question on it, it comes back on a schedule that stretches as you keep getting it right - and resets if you don't. See your review queue.
Certification
Exam objectives this topic covers
- 2.1 Configure and verify VLANs (normal range) spanning multiple switches
- 2.2 Configure and verify interswitch connectivity (trunks, 802.1Q, native VLAN)
- 2.3 Configure and verify Layer 2 discovery protocols (CDP, LLDP)
- 3.1 Interpret the components of a routing table
- 3.2 Determine how a router makes a forwarding decision by default
- 3.4 Configure and verify single area OSPFv2
- 4.1 Configure and verify inside source NAT using static and pools
- 4.3 Explain the role of DHCP and DNS within the network
- 4.4 Explain the function of SNMP in network operations
- 4.5 Describe the use of syslog features including facilities and levels
- 4.6 Configure and verify DHCP client and relay
- 4.9 Describe the capabilities and function of TFTP/FTP in the network
- 1.1 Explain concepts related to the OSI reference model
- 2.1 Explain characteristics of routing technologies
- 2.2 Configure switching technologies and features
- 3.1 Explain the purpose of organizational processes and procedures
- 3.3 Explain disaster recovery concepts
- 3.4 Given a scenario, implement IPv4 and IPv6 network services
- 5.1 Explain the troubleshooting methodology
- 5.3 Troubleshoot common issues with network services
- 5.3 Given a scenario, troubleshoot common issues with network services
- 5.4 Given a scenario, troubleshoot common performance issues
- 5.5 Troubleshoot and resolve general networking issues
- 5.5 Given a scenario, troubleshoot and resolve general networking issues