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Difficulty: MediumTroubleshooting DNS and Name Resolution Services

A network administrator is troubleshooting an issue where a client workstation is resolving an outdated IP address for a local server. Arrange the standard operating system name resolution steps in order from FIRST evaluated source to LAST evaluated source during a hostname lookup request.

  1. 1Check the local HOSTS file for static entry mappings.
  2. 2Query the local DNS client resolver cache.
  3. 3Send a recursive DNS query to the configured primary DNS server.
  4. 4Perform a Link-Local Multicast Name Resolution (LLMNR) or NetBIOS broadcast query on the local subnet.

Answer

The correct order of name resolution sources evaluated by the client operating system is: (1) Local HOSTS file, (2) Local DNS resolver cache, (3) Configured primary DNS server, and (4) Link-Local Multicast Name Resolution (LLMNR) / NetBIOS local broadcast fallback.
Standard client operating systems perform hostname resolution by inspecting local static overrides (HOSTS file) first, followed by the memory-resident DNS resolver cache, then issuing a DNS query to the designated primary DNS server, and finally using multicast/broadcast methods (such as LLMNR or NetBIOS) as a fallback mechanism if DNS resolution is unsuccessful.

Step-by-Step Solution

1
Evaluate local file-based overrides
The operating system checks the HOSTS file on disk to see if a manual IP mapping overrides network resolution.
Local static mappings take absolute priority in standard operating system resolution logic.
2
Inspect client resolver memory cache
If no entry exists in HOSTS, the OS checks volatile RAM cache managed by the DNS client service.
Checking cache minimizes network overhead and avoids unnecessary DNS queries across the LAN.
3
Query network-configured primary DNS server
If absent from local cache, a unicast DNS query is sent to the primary DNS IP address configured via DHCP or static IP settings.
This queries the authoritative infrastructure to resolve central domain names.
4
Execute local broadcast/multicast fallback mechanisms
If standard DNS infrastructure resolution yields no answer, local multicast (LLMNR) or broadcast (NetBIOS) packets are sent to adjacent subnet peers.
Broadcast mechanisms serve as a last resort for peer-to-peer name resolution within the same broadcast domain.

Key Concept

Standard Operating System Hostname Resolution Order
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Topics

Troubleshooting DNS and Name Resolution Services

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