About HOST InputBox

Now, i need a input host box, but can't use the winAPI because the api sysIPAdress have the "." in the box , i need a box empty to input HOST and the box can judge the xxx.xxx.xxx.xxx format, only the format and the xxx is number... How can do it.

Now use the ${WordFind} $Var "@,#,$,%,^,&,*,),(,-,+,],[,},{,;,',?,>,<,/," $R0

But the way i don't agree, can i have another way to solve?????