CHALLENGE 114 routers
Virtual Link Across the Transit Area
INCIDENT
The remote site can still reach head office, but nothing at head office can reach the remote site.
Ten more broken networks, labs 11 to 20, in the same shape as the first pack. Virtual links, authentication, filter lists, reference bandwidth and default origination on the OSPF side; aggregation, communities, conditional advertisement, AS path loop prevention and administrative distance on the BGP side.
Every lab deploys already broken. You diagnose it, fix it, and the verifier checks the behaviour on both the control plane and the data plane before the reveal explains the mechanism.
Ten challenges, five OSPF and five BGP, numbered on from the first pack. Each one isolates a single behavior, and the difficulty decides how much the scenario tells you before you start.
The remote site can still reach head office, but nothing at head office can reach the remote site.
One router dropped off the network after a security change, and its interface never went down.
A test subnet everyone thought was hidden is reachable from production, and the test rack has lost its route back.
Half the traffic to the data centre is slow, and it changes which half from one day to the next.
Nothing at the site can reach the internet, and both internet routers say their configuration is unchanged.
The provider session keeps dropping and coming back, and the site is unreachable from outside while it is down.
A partner says they can see a prefix of ours that is supposed to stop at our provider.
Traffic from outside is arriving over the backup circuit while the primary is up and healthy.
Two sites of the same customer stopped being able to reach each other, and the provider says it is advertising both.
A neighboring network became unreachable, and BGP says the route to it is fine.
One price, everything included. No account, no subscription. The first pack is sold separately and neither needs the other.
All ten labs, yours to keep.
How a lab works, what a scenario looks like from the inside, and the setup, are all on the main page and in the guide. Lab 01 is free, and it is the fastest way to see whether this suits you.
Built by a network engineer, for network engineers.
Adjacency Labs grew out of the way real network problems are solved: start with the symptom, inspect the state, form a theory, make a change, and verify the result. The goal is to build troubleshooting judgment, not teach another sequence of commands.