Usually dhclient.leases file is located at /var/lib/dhcp3/dhclient.leases, type le suivant command:
less /var/lib/dhcp3/dhclient.leases
OR
cat /var/lib/dhcp3/dhclient.leases
OR
Vous pouvez juste use grep command to get DHCP server address, enter:
grep dhcp-server-identifier /var/lib/dhcp3/dhclient.leases
OR
dhclient eth0