'Check dependencies and warn about firewalling'

@classmethod
def setup(cls):

    pathCheck('brctl', moduleName='bridge-utils')
    for table in ('arp', 'ip', 'ip6'):
        cmd = ('sysctl    net.bridge.bridge-nf-call-%stables' % table)
        out = quietRun(cmd).strip()
        if out.endswith('1'):
            warn('Warning:    Linux    bridge    may    not    work    with', out, '\n')
