What is DNS?

DNS stands for the Domain Name System. DNS stores the information necessary—namely the IP address, or a way to find an IP address—to locate and resolve the name to the associated content. Each entry has a few attributes:

  • Name: this is how DNS will find the entry. For example: example.com
  • Type: This dictates how the value of the entry is interpreted. Here are a few record types of note:
    • A Record: The entry directly resolves to an IPv4 address.
    • AAAA Record: The entry directly resolves to an IPv6 address.
    • CNAME Record: Resolving this entry will instead resolve to whatever the value of this record resolves to. For instance, a CNAME record associating example.com with some-infrastructure.example.com will resolve as if there were duplicate entries for the same IP address at both example.com and some-infrastructure.example.com.
    • TXT Record: The entry is not interpreted, but instead hold arbitrary data. This is useful for using DNS for other utilities, like SPF/DKIM email validation.
  • TTL: This field of the record dictates the maximum time an entry is allowed to be cached, and functions as an upper bound on how long it takes for you to expect to see the DNS changes to be visible at different parts of the internet.
  • Class: Should almost always be IN.
  • Value: The data associated with the name. How the data is interpreted is type-dependent.


I'm having SPF issues

First, check whether your SPF/TXT record has a valid value; there are tools around the internet (e.g. this one) to test configurations. If those tools show that the SPF entry is valid, check the configuration of the mail server.

I'm not seeing the DNS changes I expected

If you used a high TTL value, you may wait quite a while to see the results around the world. Setting a low TTL for an entry is crucial to seeing (and verifying) your changes quickly, so we highly recommend using a TTL of 120 seconds or lower.

I'm not sure my custom domain is configured correctly

You should see the expected DNS configuration on your “Customize Page” section of the dashboard under the “URL” tab. Here’s what it should look like if we’ve found you need to change something:

And here’s what it looks like when everything is appropriately configured: