DNS, the foundation of any internet business
Sometimes someone changes a public DNS record for a website or changes the MX record and, then, has to roll back.
Following this change, it is not uncommon for people to forget to document this action. You can therefore find yourself in a situation where your company’s sites no longer work or the emails no longer arrive.
Unlike your internal DNS there is no ‘backup’ of your public DNS (apart from a few registrars which allow access to old versions).
To obtain the history of public DNS records, there are paid sites. However, there are also free alternatives.
SecurityTrails
The website https://securitytrails.com is THE site to know about history and discovery DNS.
With the domain name or the record, it is possible to access the historical data by clicking on Historical Data.
You can access different types of records such as MX (email routing), name servers, etc.
It is also possible to access a set of subdomains by clicking on Subdomains.
Complete DNS
The website https://completedns.com/dns-history/ shows name server (NS) changes, but appears to have a better history than SecurityTrails.
But the drawbacks are it supports fewer TLDs than SecurityTrails (no .fr for example) and with a limitation of three queries per day.
With these two tools, no more missteps on the public DNS!
