def compare_relaxed(a, b):
    """
    >>> compare_relaxed('2a00:1450:400f:801::1010', '2a00:1450:400f:800::1011')
    True

    >>> compare_relaxed('2a00:1450:400f:801::1010', '2aXX:1450:400f:900::1011')
    False

    >>> compare_relaxed('2a00:1450:4016:800::1013', '2a00:1450:4008:c01::93')
    True

    >>> compare_relaxed('a.surfly.com', 'b.surfly.com')
    True

    >>> compare_relaxed('a.surfly.com', 'a.gevent.org')
    False
    """
    if a.count(':') == 5 and b.count(':') == 5:
        # IPv6 address from different requests might be different
        return True
    return a.split('.', 1)[-1] == b.split('.', 1)[-1]