simply add the file to /etc/dhcp/dhclient-exit-hooks.d/ on the next DHCP renew it will blink the numbers of the IP address
Example: 192.168.0.10
1 blink (1) 1 sec pause 9 blinks (9) 1 sec pause 2 blinks (2) 4 sec pause (.) 1 blink (1) 1 sec pause 6 blinks (6) 1 sec pause 8 blinks (8) 4 sec pause (.) 1 long blink (0) 4 sec pause (.) 1 blink (1) 1 sec pause 1 long blink (0)