One of our clients validates email addresses in their own software prior to firing it via an API call to our system. The issue is however that their validation rules do not match those our system, therefore they are parsing and accepting addresses which break our rules. This is causing lots of failed calls.
They are parsing stuff like "dave@-whatever.com", this goes against RFC 952/RFC 1123 rules as it begins with a hyphen. They have asked that we provide them with our regex list so they can update validation on their platform to match ours.
So, I need to find/build an RFC 952/RFC 1123 accepted. I found this in another SO thread (i'm a lurker :)), would it be suitable and prevent these illegal domains from being sent?