If assigning of ip address through DHCPv4 fails initscript exits with error.
Static IPv4 and IPv6 addresses are not set if DHCPv4 fails.
Add option IPV4_FAILURE_FATAL. This option lets user decide whether the script should continue or exit if DHCPv4 fails. Also if set to "no" and DHCPv6 is enabled in the configuration file, script tries to get IPv6 address even if DHCPv4 fails.
User has more control of what happens when DHCPv4 fails