--- issues: - In kernels < 3.19 net.ipv4.ip_nonlocal_bind was not a per-namespace kernel option. L3 HA sets this option to zero to avoid sending gratuitous ARPs for IP addresses that were removed while processing. If this happens then gratuitous ARPs are going to be sent which might populate ARP caches of peer machines with the wrong MAC address. fixes: - Versions of keepalived < 1.2.20 don't send gratuitous ARPs when keepalived process receives SIGHUP signal. These versions are not packaged in some Linux distributions like RHEL, CentOS or Ubuntu Xenial. Not sending gratuitous ARPs may lead to peer ARP caches containing wrong information about floating IP addresses until the entry is invalidated. Neutron now sends gratuitous ARPs for all new IP addresses that appear on non-HA interfaces in router namespace which simulates behavior of new versions of keepalived.