Well, about the valid subnets I left out ... I guess I'm just prejudiced. HHOJ.

But seriously, folks, I was going of the top of my head for masks, and missed some. I thought I was ~so~ crafty! As I reflected later while drooling on a table in a meeting, it would be better to test by powers of 2, maybe ... I still have crusty residue on the corners of my mouth.

For contiguous ones followed by contiguous zeros, I do test, actually. That's what $net tracks ... if we get an octet other than 255 or 0, set it to one. If any of the subsequent octets have a value other than 0, it's no good.

I think I like your solution better. I'll play w/ it.

Thanks to all two of you who responded thus far!

HTH
--
idnopheq
Apply yourself to new problems without preparation, develop confidence in your ability to to meet situations as they arrise.

~ Shunryu Suzuki