The Domain Name System maps names people use, such as example.com, to data computers need, such as an IPv4 or IPv6 address. It is distributed: no single server holds every answer.
The lookup path
The application checks nearby caches
Your browser and operating system may already have a recent answer. If so, no full lookup is necessary.
The recursive resolver does the work
Your device asks a resolver, often provided by the router, ISP, workplace, VPN, or a public DNS service.
The resolver follows referrals
If the answer is not cached, the resolver can ask root, top-level-domain, and authoritative name servers to locate the final record.
The answer is cached
The resolver and client store the response for a period controlled by its time to live, reducing delay and repeated traffic.
The application connects
DNS provided an address; the browser still must establish a transport connection and negotiate encryption before requesting content.
Common DNS record types
| Type | Purpose | Example use |
|---|---|---|
| A | Maps a name to an IPv4 address | A website endpoint |
| AAAA | Maps a name to an IPv6 address | An IPv6-capable endpoint |
| CNAME | Aliases one name to another | www pointing to a hosting name |
| MX | Names mail exchangers and priority | Where inbound email is delivered |
| TXT | Stores text used by many protocols | Email authentication and domain verification |
| NS | Delegates a DNS zone to name servers | Authoritative hosting for a domain |
| PTR | Maps an address back to a name | Reverse DNS, often used in mail checks |
| CAA | States which certificate authorities may issue | Certificate policy |
Caching, TTL, and “DNS propagation”
Each record has a time to live (TTL) that tells caches how long they may reuse it. When a record changes, some resolvers may still return the older cached value until that TTL expires. This staggered transition is often called propagation, although the new record is not being pushed to every DNS server.
Lowering a TTL before a planned migration can shorten the cache window, but it also increases query load. Raising it later improves cache efficiency.
What changing your DNS resolver can improve
A different recursive resolver can help when the current one is unreliable, slow to answer, filters domains unexpectedly, or lacks a feature you need. Resolver location and routing can also influence which content-delivery endpoint some services choose.
Changing DNS does not increase the capacity of the Wi-Fi link or ISP plan. Once an address has been resolved and a connection established, bulk transfer performance is governed elsewhere.
Encrypted DNS
Traditional DNS queries are commonly sent without encryption. DNS over HTTPS (DoH) and DNS over TLS (DoT) encrypt the connection between a client and compatible resolver. This can protect queries from observation or modification on that segment.
Encrypted DNS does not hide the destination from the destination itself, and other metadata may still reveal which service is being used. It also changes where policy and visibility live, which matters on managed networks.
Troubleshoot DNS on Windows
Inspect the configured resolver addresses:
Get-DnsClientServerAddress |
Where-Object ServerAddresses |
Select-Object InterfaceAlias, AddressFamily, ServerAddressesQuery a name with the default resolver:
nslookup example.comQuery a specific resolver for comparison:
nslookup example.com 1.1.1.1Clear the local Windows DNS client cache when you suspect a stale local answer:
ipconfig /flushdnsIf a name fails, check whether the failure affects one domain or many, one device or all devices, and both A and AAAA lookups. A timeout is different from a valid “name does not exist” response and points to a different next step.