The DHCP rules in the fixed iptables firewall rules were too permissive.
They permitted any UDP traffic with a source port of 68 and destination
port of 67. Care must be taken since these rules return before the IP
spoofing prevention rules. This patch splits the fixed DHCP rules into
two, one for the discovery and request messages which take place before
the instance has bound an IP address and a second to permit DHCP
renewals.
Conflicts:
neutron/tests/functional/agent/test_firewall.py
Change-Id: Ibc2b0fa80baf2ea8b01fa568cd1fe7a7e092e7a5
Partial-Bug: #1558658
(cherry picked from commit 6a93ee8ac1)