def METHOD_NAME(hostString):
    a = hostString.split('.')
    if len(a) != 4:
        return False
    for group in a:
        if (group.find("/")!=-1):
            group = group[:group.find("/")]
        if not group.isdigit():
            return False
        i = int(group)
        if i < 0 or i > 255:
            return False
    return True