While there are a number of web-based DNS diagnostic tools, the reader is cautioned against taking some of their pronouncements too seriously.

With the odd exception, the majority of web-based tools tend to throw "warnings" and "errors" about issues that aren't actually impacting the operation of a zone's DNS. They tend to be oblivious to the practice of hidden primaries and complain a lot about refresh and retry intervals, which for all practical purposes don't matter.

In other words, a lot of web DNS tools generate a lot of "look busy" output that doesn't actually convey anything useful. From there, people are prone to opening spurious tickets with their vendors.