Forum Moderators: buckworks
000-000-0000
555-555-1212
123-456-7890
This causes a problem since we can only communicate via snail mail (they usually leave the email out as well and we don't require it) and the whole process goes very slowly.
I have been asked to try to prevent this. Right now I just check that it 10 digits (I strip out dashes and parentheses). I was going to check that there were at least 3 diferent digits and that the whole thing is sequential (up or down), but I still think it would be too easy to trick your way thru the mechanism. I know i will never get it 100% but am looking to get almost everyone, any other suggestions?
1) check the area code (first 3 digits) against a current list of valid area code. There are various sites listing these. A basic list [cs.ucsd.edu] or NANPA [nanpa.com]
2) Check the exchange (next 3 digits). There are a few reserved exchanges such as 555 and the x11 numbers. You need to do a some searching to find the complete list.
International numbers are whole different thing and require varification bases on the country and city.