HTML5 pattern for ip adress - how to add ignore _ charakter

I have found pattern for validationg ip adress:

 pattern="((^|\.)((25[0-5])|(2[0-4]\d)|(1\d\d)|([1-9]?\d))){4}$"

But I need to add to ignore _ at all places, this is because I use input mask (it removes the _ after defocusing the field but the bootstrap validator plugin some time doesn't catch it)

So how I can add to this reges to ignore _