Synthetic Industry

Inspectable example · updated 2026-10-11

Example: a DNS zone before and after fixing the bare domain and www

A synthetic zone file showing a bare domain on a dead host and a stale www alias, the smallest fix, the records that must not change, and the four-address result table. No client work is shown.

An example, not a customer case study. Scope and evidence limitations are described below.

What this example is

This is a synthetic worked example. The domain larkbakery.example, its addresses and its providers are invented for illustration, and no website, mailbox or customer was changed. It shows the shape of the evidence that a bare-domain and www repair should produce: the zone before, the smallest change, the records that must stay identical, and a four-row result table. Real syntax differs between DNS providers.

The zone before: the bare domain points at a shut-down host, www at a parked alias

The business changed website host last month. The bare domain still has the old host's address, and www is an alias to a parking name. Mail and verification records are fine and must not be touched.

  • The bare domain shows a parking page or an error.
  • www shows the previous host's generic page.
  • Mail records are correct and in use.

If the matrix is wider than the box, scroll horizontally to read every column. Keyboard: focus the matrix and use Left/Right.

; SYNTHETIC EXAMPLE - larkbakery.example
larkbakery.example.      3600  A      203.0.113.10                     ; old host, shut down
www.larkbakery.example.  3600  CNAME  larkbakery-old.parked.example.
larkbakery.example.      3600  MX 10  mail.mailprovider.example.
larkbakery.example.      3600  TXT    "v=spf1 include:_spf.mailprovider.example -all"
selector1._domainkey     3600  CNAME  selector1.mailprovider.example.
_dmarc                   3600  TXT    "v=DMARC1; p=none; rua=mailto:reports@larkbakery.example"
shop-verify              3600  TXT    "booking-tool-verification=abc123"

The smallest change

The new host has told the owner two things: use the address 198.51.100.20 for the bare domain, and use the hostname sites.newhost.example for www. The change is two records. The preferred address is agreed as www, so the host redirects the bare domain to it with a permanent redirect. The mail, authentication and verification lines are listed as not to be touched and are compared before and after.

  • Change: the bare domain address record.
  • Change: the www alias target.
  • Unchanged by agreement: MX, SPF, DKIM, DMARC and the booking-tool verification record.

If the matrix is wider than the box, scroll horizontally to read every column. Keyboard: focus the matrix and use Left/Right.

; SYNTHETIC EXAMPLE - after the change
larkbakery.example.      3600  A      198.51.100.20                    ; changed
www.larkbakery.example.  3600  CNAME  sites.newhost.example.           ; changed
larkbakery.example.      3600  MX 10  mail.mailprovider.example.       ; identical
larkbakery.example.      3600  TXT    "v=spf1 include:_spf.mailprovider.example -all"   ; identical
selector1._domainkey     3600  CNAME  selector1.mailprovider.example.  ; identical
_dmarc                   3600  TXT    "v=DMARC1; p=none; rua=mailto:reports@larkbakery.example"   ; identical
shop-verify              3600  TXT    "booking-tool-verification=abc123"                       ; identical

The four-address result table

After the change, and again once the old record lifetimes have passed, each of the four starting addresses is followed to its end. A pass is a single final address, a 200 status and at most two redirects.

  • A failing row is reported as it is: the start address, the final address and what went wrong.
  • The certificate shown at the preferred address must be valid today and name that address.

If the matrix is wider than the box, scroll horizontally to read every column. Keyboard: focus the matrix and use Left/Right.

start address                    final address                      status  redirects  result
http://larkbakery.example        https://www.larkbakery.example/    200     1          pass
https://larkbakery.example       https://www.larkbakery.example/    200     1          pass
http://www.larkbakery.example    https://www.larkbakery.example/    200     1          pass
https://www.larkbakery.example  https://www.larkbakery.example/    200     0          pass

What this example does not show

It does not show delivery for any client, and nothing in it was measured on a live site. The record syntax, how the bare domain is pointed at an alias target and whether a provider offers flattened or alias records depend on your DNS provider, so a real repair starts from that provider's own documentation. The linked repair job lists what it excludes: moving DNS providers, moving the site or mail, and certificates that do not cover your names.

Sources and limits