CCNA 200-301 · configuration · troubleshooting

Hands-on networking labs at a real command line.

NetLab Trainer generates switching and routing labs, simulates the network you configure hop by hop, and grades your work against the running state of the topology — VLANs, trunks, STP, EtherChannel, static routes, OSPF, ACLs, NAT, DHCP and IPv6.

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34: lab topics
4: difficulty tiers
944+: questions
45 min: mock exam

Requirements — graded live

4 / 5

passVLAN 10 and VLAN 20 exist on SW1
passGi0/1 carries both VLANs as an 802.1Q trunk
passEach PC has a working default gateway
passPC1 can reach PC2 across the router
openManagement SVI is reachable from PC1

Checks re-run against the simulated network after every command — no answer key, no self-marking.

SW1 — consolelive

SW1#show interfaces trunk

Port         Mode      Encapsulation  Status     Native vlan
Gi0/1        on        802.1q         trunking   99

Port         Vlans allowed on trunk
Gi0/1        10,20,30,99

SW1#configure terminal
SW1(config)#interface range gi0/2 - 4
SW1(config-if-range)#switchport mode access
SW1(config-if-range)#switchport access vlan 20
SW1(config-if-range)#spanning-tree portfast
SW1(config-if-range)#end
SW1#ping 192.168.20.1
!!!!!  Success rate is 100 percent (5/5)

Generated topology

Inside the lab workspace

Topology, console and grading side by side — this is the actual screen

Topology

Device and link state update as you configure. Down ports and blocked links are visible, so you troubleshoot what you can see.

Console

R1#show ip route ospf
O  10.0.20.0/24 [110/20] via 10.0.99.2, GigabitEthernet0/1
O  10.0.30.0/24 [110/20] via 10.0.99.2, GigabitEthernet0/1

R1#show ip ospf neighbor
Neighbor ID   Pri  State     Address     Interface
2.2.2.2         1  FULL/DR   10.0.99.2   Gi0/1

R1#ping 10.0.30.10
!!!!!  Success rate is 100 percent (5/5)

A separate session per device, command history, context help and running-config — parsed, not faked.

Grading & hints

passOSPF adjacency is FULL on the core link
passBoth LAN prefixes are advertised in area 0
openLoopback0 is reachable from the branch

Requirements describe the objective, not the answer. Hints unlock progressively and cost score — Expert mode gives neither.

How the lab environment works

Four moving parts, all driven by simulated device state.

Simulated Cisco CLI

Config modes, interface ranges, show running-config, ping and traceroute — parsed and simulated against real device state, not scripted output.

SW1(config-if)#switchport mode trunk

Seeded lab generation

Every lab is generated from a seed and validated as solvable before it loads, so addressing, VLAN plans and topologies never repeat.

lab --topic ospf --difficulty advanced --seed 4471

Fault injection

Working networks are broken deliberately — shut ports, wrong masks, mismatched native VLANs. Diagnose with show commands, then repair.

%LINEPROTO-5-UPDOWN: Gi0/2 changed state to down

Requirement grading

Scored against the running network: reachability, OSPF adjacencies, VLAN membership, route selection and ACL behaviour.

PASS PC1 can reach PC2 (5/5)

Theory drills and a timed exam

Labs build the hands, question banks build the recall. Every set is randomised from the bank and weighted toward the concepts you have missed before.

Practice

944 questions · 34 topics

Pick any combination of topics and a difficulty band, choose 10 to 50 questions, and get an explanation for every answer — right or wrong.

Mock exam

40 questions · 45 minutes

Domain-weighted, free navigation, no feedback until you submit — then a per-topic breakdown showing exactly where to revise.

Topic coverage

Four difficulty tiers per topic · free command reference on every topic

Mapped to the CCNA 200-301 blueprint

Every topic sits in one of the six published exam domains

1.0 · 20% of the exam

Network Fundamentals

IPv4 Addressing · Subnetting · VLSM · IPv6 Addressing · CDP & LLDP

5 lab topics

2.0 · 20% of the exam

Network Access

VLANs · Access Ports · Trunking · STP · EtherChannel · Advanced STP · Advanced EtherChannel · Wireless LANs

8 lab topics

3.0 · 25% of the exam

IP Connectivity

Inter-VLAN Routing · Static Routing · Default Routes · OSPF · IPv6 Routing · OSPF for IPv6 · Troubleshooting

7 lab topics

4.0 · 10% of the exam

IP Services

DHCP · DHCP Relay · NAT · DNS & Network Services · QoS

5 lab topics

5.0 · 15% of the exam

Security Fundamentals

ACLs · IPv6 ACLs · Port Security · SSH & Device Security · DHCP Snooping · Dynamic ARP Inspection · Wireless Security

7 lab topics

6.0 · 10% of the exam

Automation & Programmability

Device Management · Programmability

2 lab topics

Common questions

Is this a real Cisco simulator?: It is an independent simulation of IOS behaviour built for exam practice — commands are parsed and evaluated against a modelled network, not replayed from a script. It is not affiliated with or endorsed by Cisco Systems, Inc.
Do I need an account to start?: Yes, a free account. It stores your progress, XP and streaks, and gives you 5 Beginner lab attempts every day plus unlimited practice questions.
How are labs graded?: Each lab carries weighted requirements checked against the running network — reachability, adjacencies, VLAN membership, route selection and ACL behaviour. Hints reduce your score; nothing is marked by hand.
What does Premium add?: Unlimited lab attempts at every difficulty, troubleshooting labs with injected faults, and the timed 40-question mock exam. Cancel recurring billing any time from your account.
Does the same lab repeat?: No. Labs are generated from a seed and validated as solvable before they load, so addressing, VLAN plans and topologies differ on every run.
Does it work on a phone?: Practice questions and the reference work well on mobile. The lab console is usable but genuinely better on a laptop with a keyboard.

Open a console and configure something.

5 Beginner lab attempts per day, practice questions unlimited.

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