Validating IP ranges / text

Hi All!

I am still relatively new to working with the more advanced features of Excel, but I am getting a lot better - in part thanks to help I've found here = ) I've recently come across a pretty complex problem to solve, and I was hoping to get some input.


I've been asked to validate entries in a column of a worksheet - only allowing valid IP address ranges to be entered OR text that specifically says "None." I don't really have control over the process that hands down these requests, but I am pretty much expected just to implement them as requested if at all possible.

I know how to do basic data validation, but given some ranges of valid IP addresses and requiring Excel to check entries against that list OR against the word "None" is kind of beyond my abilities at this stage. Is this something that can even be done with basic validation, or do I need to try to code this in VBA somehow? OR - at the least, I assume it is possible to require a certain sequence to validate (like 1 to 3 characters, a dot, 1 to 3 characters, a dot, 1 to 3 characters, a dot, and 1 to 3 characters) - but I have had trouble allowing multiple dots ("."s) in one cell - apparently Excel does not like this ; )

I've looked online and in the forum, but haven't found anything really helpful (other than one for-purchase programs that would do it automatically...).


Any suggestions for the right direction would be very very helpful. Thanks so much for any hints / suggestions you may have!!