Frankly, I'd almost consider a lack of support for those forms a feature. I've never seen anyone use them in good faith; using them is almost always either 1) a

Frankly, I'd almost consider a lack of support for those forms a feature. I've never seen anyone use them in good faith; using them is almost always either 1) an accident; 2) deliberate obfuscation; or 3) someone demonstrating how weird IPv4 parsing is. Yes, I know it's probably required by a spec. There's lots of weird old things in specs. Not all of them are sensible.