So a website is not loading, and you have no idea where to start. Before you blame your ISP or restart the router for the fourth time, there is a good chance the issue lives in DNS. A DNS lookup is the fast, boring, reliable first check that separates "my setup is broken" from "the domain just is not pointing anywhere right." Let me walk you through how it works and how to run one without memorizing a bunch of commands.
What Is a DNS Lookup, Really?
Every device on the internet is tracked by numbers, not names. When you type ipipai.com into your browser, something has to translate that friendly name into an IP address like 8.8.8.8. That translation is what DNS (Domain Name System) does. A DNS lookup is simply asking "what does this domain point to right now?" and getting the answer back.
Here is the thing that surprises people: DNS is a distributed, layered phone book. Your device asks its local resolver (usually your ISP or a public one like 1.1.1.1), which may check the root servers, then the TLD servers, then the domain's own name servers before the final IP comes back. Most of that happens in milliseconds and you never see it. But when one link in that chain is wrong, the website dies quietly.
The Record Types You Actually Care About
A single domain can carry many different records at once. Each one answers a different question. Here are the ones you will touch constantly:
- A record — maps a domain to an IPv4 address. This is the one that decides where the website actually lives. If your A record is wrong, the site does not open, full stop.
- AAAA record — the IPv6 version of an A record. Most modern networks can use these, so a healthy domain usually has both.
- MX record — points email for the domain at the mail server that should receive it. No MX, no incoming mail. This one bites people who think "the website is up, why is my email dying?"
- TXT record — free-form text used for things like email verification, SPF, and domain ownership proofs. It is how a lot of services confirm you control a domain.
There are plenty of others (CNAME, NS, SOA, SRV, and so on), but if you can read those four, you can debug almost every real-world domain problem. The rest show up the moment you dig deeper.
How I Would Run a DNS Lookup
Depending on your comfort with a terminal, you have two clean paths. IPIPAI's resolve_dns tool at https://ipipai.com/api/dns-resolve?domain=... takes the command line out of the picture entirely — you just drop a domain in and read the answer. For people who live in a terminal, the classics are dig and nslookup:
dig ipipai.com A dig ipipai.com MX dig ipipai.com TXT
The IPIPAI API returns the records as structured JSON, which makes it easy to script. And if you are building something that needs to resolve domains automatically, the resolve_dns MCP tool does the same job inside an AI agent — no API key for basic queries, and it sits right next to the other network tools like ping_host and trace_route. More on that below.
Reading What Comes Back
A raw dig result looks dense, but most of it is noise. What you want is the ANSWER SECTION — that is where the actual records live. A few things to watch for:
- No A/AAAA at all — the domain does not resolve to anything. The site is effectively unreachable by IP, which is why nothing loads.
- A record present but pointing to the wrong IP — the site might be down on the other end, or someone pointed it at a dead server.
- MX missing or stale — email fails even when the website looks fine. These two often break independently.
- TXT missing when you expected one — verification, SPF, and DKIM checks will not pass, and some mail providers reject the domain for it.
Catch a NXDOMAIN and that means the name does not exist at all — usually a typo, or a domain that was never registered or has fully dropped. That is a very different problem from "it exists but points nowhere."
When DNS Is Not the Culprit
Do not sleep on one thing: even a perfectly correct record can still fail to show up because of caching. DNS answers are cached everywhere — in your browser, in your OS, on your router, and at every resolver along the way. That cache has a TTL (time to live) and it will happily keep handing out the old answer until it expires. So if you changed your DNS and "nothing happened," wait the TTL out, or flush your cache, before you convince yourself the change did not go through.
For the bigger picture of where an address really lives, the IP lookup tool is the natural companion to a DNS answer. Want to understand the ping numbers you are about to see? The ping test explained article is a good refresher.
Using the resolve_dns MCP Tool
If you are wiring network checks into an AI agent, the resolve_dns tool is one of the 11 IPIPAI exposes over the MCP server. You call it by name, pass a domain, and the agent gets clean structured records back to reason about. It is the same endpoint behind the web tool — /api/dns-resolve?domain=... — just exposed to models. Pair it with trace_route and you have a small, self-contained network diagnostic that an agent can run end to end without anyone typing a command.
Wrapping Up
A DNS lookup is five seconds of work that saves you an hour of guessing. Type the domain into IPIPAI's resolve_dns tool, check your A/AAAA first, peek at MX and TXT if the problem smells like email or verification, and keep caching in the back of your mind. And when the name resolves but the connection still misbehaves, that is the moment to hand off to traceroute and ping. The rest of the blog is on the IPIPAI articles page if you want to keep going.