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IUP ITS: Networking and Network Infrastructure

IUP ITS · Work through your exam, one topic at a time.

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Networking and Network Infrastructure

Networking and Network Infrastructure tests whether you can explain how data moves, isolate faults by layer, and apply addressing and service configuration without guessing.

Core rules

  • Troubleshoot in order: physical/link, IP, transport, application. Check cable or Wi-Fi, then IP configuration, then DNS, then the application.
  • IPv4 private ranges are 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16. APIPA 169.254.0.0/16 usually means DHCP failed.
  • A /26 has 64 addresses and 62 usable hosts. Network and broadcast addresses are not assignable.
  • Switches forward within VLANs; routers forward between subnets. VLANs separate broadcast domains.
  • DHCP supplies address, mask, gateway, and DNS; DNS resolves names. A reachable IP with failed name resolution points to DNS.
  • NAT translates private to public addresses. It is not a firewall substitute.

Worked example

A workstation cannot reach intranet.example.com by name but can ping 10.20.4.15. The IP stack works. The workstation shows address 169.254.8.22 and no gateway. The likely fault is DHCP, not DNS. Renew DHCP; if the address remains APIPA, check the VLAN, switch port, and DHCP scope before changing DNS settings.

Traps

Do not count network and broadcast addresses as usable. Do not confuse the default gateway with the DNS server. Do not treat a VLAN as a security boundary by itself. Do not blame the WAN before testing the local link and IP configuration. Wireless faults often involve signal, channel, authentication, or DHCP, not just the internet.