'Test ICMP net unreachable packets get back
When destination address of ip traffic is not reachable, ICMP packets
are returned. This packets are marked as RELATED traffic by conntrack
and this test case validates such packets are not dropped by the
firewall as ingress ICMP packets are not allowed in this test case. The
used address below 1.2.3.4 is outside of subnet that is used in tester
object.'

def test_related_connection(self):

    self.tester._peer.execute(['sysctl', '-w', ('net.ipv4.conf.%s.forwarding=1' % self.tester._peer.port.name)])
    self.tester.set_vm_default_gateway(self.tester.peer_ip_address)
    vm_sg_rules = [{'ethertype': 'IPv4', 'direction': 'egress', 'protocol': 'icmp'}]
    self._apply_security_group_rules(self.FAKE_SECURITY_GROUP_ID, vm_sg_rules)
    self.tester.assert_net_unreachable(self.tester.EGRESS, '1.2.3.4')
