in resolver/src/main/java/org/apache/james/jspf/core/Inet6Util.java [369:381]
public static boolean isValidIP4Word(String word) {
char c;
if (word.length() < 1 || word.length() > 3)
return false;
for (int i = 0; i < word.length(); i++) {
c = word.charAt(i);
if (!(c >= '0' && c <= '9'))
return false;
}
if (Integer.parseInt(word) > 255)
return false;
return true;
}