Diagnose a configuration from four commands and write down what each proved

short · 30 min · Objective 1.2

Task

Run the five diagnostic network commands on a machine, record what each one returned, and state what each result eliminated. The exercise is the reasoning rather than the typing: the value of ipconfig /all is that four of its values each rule out a different fault.

Steps

  1. Run the address command for your platform and write lab/cli/config.csv with header value,what_it_is,what_it_rules_out covering address, mask, gateway, DNS servers and DHCP server.
  2. Ping the gateway, then an address on the internet, then a name. Record all three in lab/cli/chain.csv with header target,result,layer_proved.
  3. Run the name resolution command against a name and record which server answered in lab/cli/dns.txt.
  4. Run the connections command and write lab/cli/listening.csv with header port,state,process,expected listing at least five listening ports on the machine, marking whether you expected each one.
  5. Write lab/cli/elevation.md naming three commands that need administrative rights, and describing what the file system virtualisation trap does to a write that is not elevated.

Verify

awk -F, 'NR>1 && NF>=3 {n++} END {print n" value(s) explained"}' lab/cli/config.csv
awk -F, 'NR>1 && NF>=3 {n++} END {print n" test(s) in the chain"}' lab/cli/chain.csv
grep -c . lab/cli/dns.txt
awk -F, 'NR>1 && NF>=4 {n++} END {print n" listening port(s)"}' lab/cli/listening.csv
awk -F, 'NR>1 && $4 ~ /no/ {n++} END {print n" unexpected port(s)"}' lab/cli/listening.csv
grep -Eic 'administrator|elevat|virtualis|virtualiz' lab/cli/elevation.md

Five configuration values each with a fault it rules out, three chain tests, and five listening ports assessed. An unexpected port is a finding worth following up rather than a mistake in the lab.

Notes

The what_it_rules_out column is the whole exercise. An address beginning 169.254 rules out a working DHCP server and rules IN a functioning adapter and stack, and being able to say both halves is what distinguishes reading output from understanding it.

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