Network Administrator interview loops

A network administrator keeps an organisation's switches, Wi-Fi, internet links, VPNs, DNS and DHCP, and firewalls working for people who only notice the network when it stops. Most weeks are tickets and small changes. What decides the hire is the moment the explanation and the evidence part company: the failover probe says the link is up while forty people cannot load a page, an approved change contains a command that takes two floors off the network, a firewall rule with no hits turns out to be the one the disaster-recovery plan depends on. The role here is the network; servers, backups and identity belong to a system administrator and are not read in these rounds.

Networking is unusually easy to prepare for on paper. The layers of the OSI model, TCP against UDP, what a VLAN is and how a subnet mask works all have short, correct answers, and a candidate can give every one of them without ever having read an interface counter during an outage. The failures that cost an organisation are different in kind: mostly quiet, and often self-inflicted — a health check that tests the wrong device, a trunk command that replaces a list it was meant to extend, a temporary rule that turned two years old. So the rounds below do not ask for definitions. Each gives the candidate something an interviewer can prepare in an evening, in the syntax of their own equipment: evidence cards handed over one request at a time, three packet captures of the same stalled file copy, someone else's change request, a rulebase export. Then the round scores what the candidate does with it.

A loop is a set of round plans in order. Each round scores one to three competencies, every must-have is scored in at least two rounds, and the debrief goes competency by competency rather than round by round, so no single interview decides the hire. How these plans work covers the rest of the method.