DNS (Domain Name System) is often called the "phonebook of the internet." It translates human-readable domain names like whatip.ca into machine-readable IP addresses like 192.0.2.1. Without DNS, you'd have to memorize IP addresses for every website you want to visit.
The DNS Resolution Process
When you type a URL into your browser, here's what happens behind the scenes:
Step 1: Browser Cache Check
Your browser first checks its own cache to see if it recently looked up this domain. If found, it uses the cached IP immediately.
Step 2: Operating System Cache
If not in browser cache, the request goes to your operating system, which also maintains a DNS cache.
Step 3: Recursive Resolver
If still not found, the query goes to a recursive DNS resolver — typically operated by your ISP or a public DNS service like Google (8.8.8.8) or Cloudflare (1.1.1.1).
Step 4: Root Name Servers
The resolver contacts one of the 13 root name server clusters. These don't know the final IP, but they know which servers handle each top-level domain (.com, .org, .ca, etc.).
Step 5: TLD Name Servers
The root server directs the resolver to the TLD (Top-Level Domain) server. For whatip.ca, this would be the .ca TLD servers.
Step 6: Authoritative Name Server
The TLD server points to the authoritative name server for the specific domain. This server has the actual DNS records and returns the IP address.
Step 7: Response & Caching
The IP address travels back through the chain. Each server caches the result for faster future lookups (based on the TTL — Time To Live).
This entire process typically takes just 20-120 milliseconds. Caching at multiple levels means most queries are resolved without going through all steps.
Types of DNS Servers
| Server Type | Role | Example |
|---|---|---|
| Recursive Resolver | Does the lookup work on behalf of the client | 8.8.8.8 (Google), 1.1.1.1 (Cloudflare) |
| Root Server | Points to TLD servers | a.root-servers.net |
| TLD Server | Handles top-level domains | .com, .org, .ca servers |
| Authoritative Server | Has the actual DNS records | Your domain's nameservers |
Common DNS Record Types
| Record | Purpose | Example |
|---|---|---|
| A | Maps domain to IPv4 address | whatip.ca → 192.0.2.1 |
| AAAA | Maps domain to IPv6 address | whatip.ca → 2001:db8::1 |
| CNAME | Alias pointing to another domain | www → whatip.ca |
| MX | Mail server for the domain | Priority 10: mail.example.com |
| TXT | Text data (SPF, DKIM, verification) | v=spf1 include:_spf.google.com ~all |
| NS | Nameservers for the domain | ns1.example.com |
DNS Caching & TTL
Each DNS record has a TTL (Time To Live) value that tells resolvers how long to cache the record. Common TTL values:
- 300 seconds (5 min): For records that change frequently
- 3600 seconds (1 hour): Standard for most records
- 86400 seconds (24 hours): For stable records
When you change DNS records, the old records may persist in caches worldwide until their TTL expires. This is why DNS changes can take up to 48 hours to fully propagate.
Checking DNS Records
You can query DNS records using command-line tools:
# Using nslookup
nslookup whatip.ca
# Using dig (more detailed)
dig whatip.ca A
dig whatip.ca MX
dig whatip.ca TXT
# Query a specific DNS server
dig @8.8.8.8 whatip.caOr use our DNS lookup tool for a visual, easy-to-read output.
Check Any Domain's DNS Records
Use our free DNS lookup tool to see A, MX, TXT, and other records.
DNS Lookup Tool