SiteSmith

DNS explained for small business owners

SiteSmith · · 5 min read

DNS, short for Domain Name System, is the internet's address book. When someone types your domain into a phone, DNS looks up which computer holds your website and sends them there. When someone emails you, DNS tells their mail service which company receives mail for your business. Your domain's entry in that address book is a short list of records, and knowing what each kind does takes most of the fear out of changing a website or email provider.

The address book, for one business

Picture your domain as a single page in a big shared address book. The page has a few lines on it, each one answering a different question:

  • "Where is the website?"
  • "Where is the website with www in front?"
  • "Where do I deliver mail?"
  • "Who is allowed to send mail for this business?"
  • "Who keeps this page up to date?"

Every phone, laptop and mail server in the world can read the page, but only whoever holds your DNS login can change it. That is all DNS is. It holds no website files and no emails; it only says where they live.

The records you will actually see

When you open the DNS screen at GoDaddy, Namecheap, Squarespace or anywhere else, you see a table of records. Each row has a type, a name (sometimes called host), a value (sometimes called points to, data or target) and a TTL. Here is what the common types mean.

A record: the street address

An A record links a name to an IP address, a number like "192.0.2.10" that identifies one computer on the internet. The A record for the bare domain is what sends visitors to your website. When you switch website providers, this is usually the line that changes.

AAAA record: the newer street address

The same idea as an A record, for the newer, longer kind of internet address. Many small sites do not have one. If you have one left over from an old host, it can send some visitors to the old site after a switch.

CNAME record: "see the entry for..."

A CNAME is a nickname. Instead of an address, it says "this name is the same as that other name, look it up there". It is common for "www": "www.yourbusiness.com" might be a CNAME to "yourbusiness.com", or to a name your website provider gives you. A CNAME and other records cannot share the same name, which is why DNS screens sometimes refuse to save one.

MX record: the mailroom

MX stands for mail exchanger. These records say which company accepts email for your domain. A business on Google Workspace has MX records pointing at Google; a business on Microsoft 365 has one pointing at Outlook. Each has a number called priority: lower numbers are tried first, higher numbers are backups.

Delete or change these and your email stops arriving, often without any error you would notice. They have nothing to do with your website, so when you change websites, leave them alone.

TXT record: notes for other systems

TXT records hold short pieces of text that other services read. The common ones for a small business:

  • SPF, starting "v=spf1", lists the services allowed to send email as you. It helps your mail reach inboxes rather than spam.
  • DKIM and DMARC, more email trust settings, often with "_domainkey" or "_dmarc" in the name.
  • Verification codes from Google, Microsoft, Facebook or others, proving you control the domain.

If you want to understand the email trust trio properly, SPF, DKIM and DMARC explains them one at a time.

NS record: who keeps the page

NS records name the nameservers, the company that holds your page in the address book. They are set at the registrar where your domain is registered. Changing them hands the whole page to another company. The difference between changing these and changing individual records is big enough to have its own guide: nameservers vs DNS records.

What the names mean

The name column trips people up, because providers write it differently:

  • "@" means the bare domain itself, "yourbusiness.com". Some screens leave it blank or write the full domain instead.
  • "www" means "www.yourbusiness.com".
  • Any other word, like "shop", "book" or "mail", means that word in front of your domain: "shop.yourbusiness.com". These are called subdomains, and each can point somewhere different.

TTL: how long others remember

TTL means time to live. It is a number of seconds that tells other computers how long they may remember an answer before asking again. A TTL of 3600 means an hour. That is why a change you make is not seen everywhere instantly: some phones and internet providers are still using the answer they remembered. Lower TTLs mean faster updates; most owners can leave the default.

A sample page, written out

Here is roughly what the DNS for a small bakery on Google Workspace might look like, in plain words:

  • A, name @: the website host's IP number. This is the website.
  • CNAME, name www: the bare domain. This is the website with www in front.
  • MX, name @: Google's mail servers. This is where email is delivered.
  • TXT, name @: "v=spf1 include:_spf.google.com ~all". This says who may send mail as the bakery.
  • TXT, name @: "google-site-verification=" followed by a code. This proves ownership to Google.

To change the website, you would touch the first two lines. To change email providers, the MX and SPF lines. Nothing else.

Things DNS does not do

  • It does not move your website. Changing a record points people somewhere else; the files at the old host stay there until you cancel it.
  • It is not your domain registration. You can keep the domain at one company and the DNS at another.
  • It does not change your Google Business Profile, your listings or your phone number.
  • It does not delete anything when you cancel an old website. The records stay until someone edits them, which is why old records hang around for years.

What to do this week

  • Find out where your DNS lives: look up your domain on ICANN's lookup tool and read the nameservers.
  • Log in there and take a screenshot of every record.
  • Label the rows using the table above: website, email, verification.
  • Keep the screenshot with your business passwords; it is your map for any future change.

When you are ready to put a new site on your domain, connecting your domain to a new website walks through the edits, and you can see your site rebuilt first before you change a single record.

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