dhcp server function doesn't work after interface status changes from DOWN to UP
after configured /etc/default/isc-dhcp-server and /etc/dhcp/dhcpd.conf, i started isc-dhcp-server via systemctl restart isc-dhcp-server (interface is DOWN currently).
checking process status with systemctl status isc-dhcp-server, it showed like below: No subnet declaration for eno6 (no IPv4 addresses). ** Ignoring requests on eno6. If this is not what you want, please write a subnet declaration in your dhcpd.conf file for the network segment to which interface eno6 is attached. **
then i plugged in a cable into eno6, it turned to UP status, but dhcp server function seems not working, because the client didn't get any ip address.
however, if i plugged in a cable first, then start isc-dhcp-server, it worked well if i unplugged the cable and re-plugged back.
what i want to know is that can isc-dhcp-server auto detect the listed interfaces status, when interfaces turn to UP status, it will always assign ip address to client successfully without restarting process manually.
my env is Ubuntu 18.04.
thanks.