DNSTwist
If you manage domains for yourself or your organization, it might be a good idea to have an idea of similar looking/sounding domains from a security perspective. This blog isn't focused much on brand protection, although that is another use-case for being aware of similar domains to your own. There are a few methods for being aware of domains that are registered (or could be registered) that are similar to your own, one comprehensive method that requires a fair amount of work would be Rapid 7's Project Sonar data. This is a collection of datasets that are updated weekly (after you register for a free account) or monthly (downloadable without requiring any account registration). For our purposes the interesting one is the Forward DNS data which includes all A and AAAA records. Downloading this dataset is the easy part (assuming you have the harddrive space to store it, compressed the A record data is 22.9 GB as of August 2020), once you have it you need to do something with it. This involves additional parsing, storage, and notification, something that can certainly be done (and might be a fun project) but if we could shortcut getting the same or better result with a LOT less effort, well that would sure be neat...