Hi TruSouthrnPlaya and welcome to our forum!
Open the form in the InfoPath designer and double click on the field that is giving you grief. Check out the validation conditions. If you can't fix from there, do what Franck says and add another binding. You can re-validate the new binding using a regular expression based on IP format.
Patrick Halstead [InfoPath MVP]
InfoPathDev
Patrick Halstead
Project Manager at Qdabra