Guide
What an A record tells you and how to read the result
When a website does not load, a migration looks half done or a certificate request fails, the first question is simple: where does this name point? The A record answers it for IPv4. The page returns the addresses a resolver currently has for a name and tells you what sort of address each one is, so a misconfiguration stands out.
What the record does
An A record is the oldest and most common DNS record. It maps a host name to a 32-bit IPv4 address. A name can carry several A records, and resolvers rotate their order from one answer to the next; browsers typically try the first and fall back to the next if a connection fails. Large sites go further and publish different addresses to different regions, or put a content delivery network in front, so the addresses you see from one place are not necessarily the ones another visitor receives.
Following aliases
Many names are not A records at all but aliases. www.example.com may be a CNAME that points to a hosting provider’s name, which in turn has the A records. The resolver follows the chain for you, and the page shows the alias steps before the final addresses. If a name has a CNAME, it cannot have any other record of its own, which is why you never see both an alias and an A record at the same level. For a closer look at each hop, use the CNAME Lookup.
The kind-of-address column
Each address is classified so you notice problems quickly. Public means globally routable. Private addresses (10.x.x.x, 172.16 to 172.31.x.x and 192.168.x.x) in a public name usually mean an internal record leaked out or a mistake, and the site will not be reachable from the Internet. Loopback (127.x), link-local (169.254.x) and documentation addresses likewise indicate placeholders. The classification is the same one used by the Private IP Checker.
TTL and caching
The number beside each address is the time to live in seconds. It is the remaining life of the cached answer in the resolver, so it counts down between lookups and resets to the zone’s value when the cache is refreshed. Two lookups a few seconds apart can therefore show different TTLs for the same data. A low value, such as 300, means changes spread quickly; a high one, such as 86400, means a change can take a day to be seen everywhere.
A worked example
Press Sample to look up example.com. The page returns a table with the name, two IPv4 addresses, their TTL and the kind of address, “Public (globally routable)” for each, and the line “Answered by Cloudflare (1.1.1.1) in … ms · status NOERROR · DNSSEC validated (AD)”. Run it again and the TTL has moved down by the number of seconds elapsed. Changing the resolver to Google shows the same set of addresses, maybe in a different order and with a different remaining TTL, because each resolver has its own cache.
Limits
The result is what the chosen public resolver holds, not the zone’s master data, and it cannot show internal DNS. Geographic or load-balancing DNS can return different addresses to different resolvers, and the page cannot reproduce the view from your visitors’ locations. It also does not test that anything is listening at the address. To compare resolvers, use the DNS Propagation Checker.
Related tools
- AAAA Record Lookup shows the IPv6 addresses of the same name.
- CNAME Lookup follows alias chains hop by hop.
- Reverse DNS Lookup goes from an address back to a host name.
- DNS Lookup shows many record types at once.
Checked against the current version of the A Record Lookup on .