What they do well
MxToolbox, EasyDMARC, PowerDMARC and several others will assess a domain at no cost and do it accurately. They will tell you what your MX records are, whether SPF and DMARC exist, when your certificate expires, and what your DNS looks like right now.
That is genuinely useful and we do not claim to do it better. Our own free check exists because putting a wall around commodity information would be both pointless and slightly insulting.
The thing none of them can answer
Every one of these tools, ours included, closes the tab and forgets you existed. Run the same check next year and it starts from nothing.
Which means none of them can answer:
- When did the host change, and what was it before
- How long have we been using this mail provider
- What was that DNS record before someone edited it last spring
- What did our pricing page say in March
- Were we running that third-party script during the period of the incident
- Has any of this been watched, by whom, and since when
Why these are the questions that arrive
Nobody asks what your DNS looks like today. They ask historical questions, and they ask them in specific situations: a handover, an audit, an insurance claim, a dispute about what was advertised, a buyer doing diligence, a security review after a breach somewhere else.
All of those arrive without warning and all of them are about the past.
Why it cannot be assembled afterwards
Some of it can, given a few days: registrar emails, old invoices, a backup. Much of it cannot at any price. Nobody can tell you what a DNS record contained before it was edited unless somebody kept a copy at the time. Nobody can produce what a page said on a specific date unless it was captured.
By the time the question is asked, the window to have answered it closed some years earlier. That is the entire argument for a record that runs continuously rather than a check you run when you think of it.
So use the free tools
Really. Run ours, run MxToolbox, run whichever you like, and fix whatever they find. The paid product is not for the moment you want to know what is true. It is for the moment somebody asks you to prove how long it has been true.
The fuller argument: a monitor tells you now, a record tells you when.