import socket


def is_ipv4(v):
    """
    Check value is valid IPv4 address

    >>> is_ipv4("192.168.0.1")
    True
    >>> is_ipv4("192.168.0")
    False
    >>> is_ipv4("192.168.0.1.1")
    False
    >>> is_ipv4("192.168.1.256")
    False
    >>> is_ipv4("192.168.a.250")
    False
    >>> is_ipv4("11.24.0.09")
    False
    """
    X = v.split(".")
    if len(X) != 4:
        return False
    try:
        return len([x for x in X if 0 <= int(x) <= 255]) == 4 and bool(socket.inet_aton(v))
    except Exception:
        return False