'Uses GSSAPI to authenticate the server.
Returns True on success, False on failure.'

def authenticate_server(self, response):

    log.debug('authenticate_server():    Authenticate    header:    {0}'.format(_negotiate_value(response)))
    host = urlparse(response.url).hostname
    try:
        result = kerberos.authGSSClientStep(self.context[host], _negotiate_value(response))
    except kerberos.GSSError:
        log.exception('authenticate_server():    authGSSClientStep()    failed:')
        return False
    if (result < 1):
        log.error('authenticate_server():    authGSSClientStep()    failed:    {0}'.format(result))
        return False
    log.debug('authenticate_server():    returning    {0}'.format(response))
    return True
