Don’t trust the .NET web forms email regex validator (or most others)
I’ve been working on a little project recently that involves handling hundreds of millions of email addresses from various sources. More on that in a later post, but for now let’s just assume that I want to have a reasonable degree of confidence that each of these addresses from an untrusted source is valid. Indeed many of them are just rubbish – beyond the obvious “does it have an @ symbol”, a bunch of them don’t have dots in the domains or contain illegal characters in places where they just s...