Note that, as surprising as it may be, this doesn't prevent the DHCP server from functioning. You only get a warning in /var/log/syslog about the fact that 'None' is not a valid IP address.
Note that, as surprising as it may be, this doesn't prevent the DHCP server from functioning. You only get a warning in /var/log/syslog about the fact that 'None' is not a valid IP address.