Então provavelmente o dhclient já está rodando. Confirma p.f.
pgrep dhclient
grep -i dhcp /var/log/syslog | tail -20
cesarcostap2@cesarcostap2-To-be-filled-by-O-E-M:~$ pgrep dhclient
cesarcostap2@cesarcostap2-To-be-filled-by-O-E-M:~$
cesarcostap2@cesarcostap2-To-be-filled-by-O-E-M:~$ grep -i dhcp /var/log/syslog | tail -20
Aug 1 19:59:37 cesarcostap2-To-be-filled-by-O-E-M kernel: [ 9.692686] type=1400 audit(1406933974.557:3): apparmor="STATUS" operation="profile_load" name="/usr/lib/NetworkManager/nm-dhcp-client.action" pid=519 comm="apparmor_parser"
Aug 1 19:59:37 cesarcostap2-To-be-filled-by-O-E-M kernel: [ 9.694133] type=1400 audit(1406933974.557:6): apparmor="STATUS" operation="profile_replace" name="/usr/lib/NetworkManager/nm-dhcp-client.action" pid=518 comm="apparmor_parser"
Aug 2 12:07:40 cesarcostap2-To-be-filled-by-O-E-M kernel: [ 9.869997] type=1400 audit(1406992057.733:3): apparmor="STATUS" operation="profile_load" name="/usr/lib/NetworkManager/nm-dhcp-client.action" pid=463 comm="apparmor_parser"
Aug 2 12:07:40 cesarcostap2-To-be-filled-by-O-E-M kernel: [ 9.871327] type=1400 audit(1406992057.733:6): apparmor="STATUS" operation="profile_replace" name="/usr/lib/NetworkManager/nm-dhcp-client.action" pid=517 comm="apparmor_parser"
Aug 2 17:43:54 cesarcostap2-To-be-filled-by-O-E-M kernel: [ 9.921521] type=1400 audit(1407012231.785:4): apparmor="STATUS" operation="profile_load" name="/usr/lib/NetworkManager/nm-dhcp-client.action" pid=515 comm="apparmor_parser"
Aug 2 17:43:54 cesarcostap2-To-be-filled-by-O-E-M kernel: [ 9.921530] type=1400 audit(1407012231.785:5): apparmor="STATUS" operation="profile_replace" name="/usr/lib/NetworkManager/nm-dhcp-client.action" pid=516 comm="apparmor_parser"
Aug 4 23:33:57 cesarcostap2-To-be-filled-by-O-E-M kernel: [ 9.844080] type=1400 audit(1407206034.709:4): apparmor="STATUS" operation="profile_load" name="/usr/lib/NetworkManager/nm-dhcp-client.action" pid=499 comm="apparmor_parser"
Aug 4 23:33:57 cesarcostap2-To-be-filled-by-O-E-M kernel: [ 9.844091] type=1400 audit(1407206034.709:5): apparmor="STATUS" operation="profile_replace" name="/usr/lib/NetworkManager/nm-dhcp-client.action" pid=500 comm="apparmor_parser"
Aug 5 16:51:39 cesarcostap2-To-be-filled-by-O-E-M kernel: [ 9.909820] type=1400 audit(1407268297.774:4): apparmor="STATUS" operation="profile_load" name="/usr/lib/NetworkManager/nm-dhcp-client.action" pid=499 comm="apparmor_parser"
Aug 5 16:51:39 cesarcostap2-To-be-filled-by-O-E-M kernel: [ 9.909955] type=1400 audit(1407268297.774:5): apparmor="STATUS" operation="profile_replace" name="/usr/lib/NetworkManager/nm-dhcp-client.action" pid=498 comm="apparmor_parser"
Aug 5 16:54:19 cesarcostap2-To-be-filled-by-O-E-M dhclient: DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 3 (xid=0x14ce09b4)
Aug 5 16:54:19 cesarcostap2-To-be-filled-by-O-E-M dhclient: DHCPREQUEST of 192.168.1.2 on eth0 to 255.255.255.255 port 67 (xid=0x14ce09b4)
Aug 5 16:54:19 cesarcostap2-To-be-filled-by-O-E-M dhclient: DHCPOFFER of 192.168.1.2 from 192.168.1.1
Aug 5 16:54:21 cesarcostap2-To-be-filled-by-O-E-M dhclient: DHCPACK of 192.168.1.2 from 192.168.1.1
Aug 5 16:54:40 cesarcostap2-To-be-filled-by-O-E-M dhclient: DHCPREQUEST of 192.168.1.2 on eth0 to 255.255.255.255 port 67 (xid=0x3711410b)
Aug 5 16:54:41 cesarcostap2-To-be-filled-by-O-E-M dhclient: DHCPACK of 192.168.1.2 from 192.168.1.1
Aug 5 16:54:58 cesarcostap2-To-be-filled-by-O-E-M dhclient: DHCPREQUEST of 192.168.1.2 on eth0 to 255.255.255.255 port 67 (xid=0x62babf58)
Aug 5 16:54:59 cesarcostap2-To-be-filled-by-O-E-M dhclient: DHCPACK of 192.168.1.2 from 192.168.1.1
Aug 6 07:07:58 cesarcostap2-To-be-filled-by-O-E-M kernel: [ 9.857924] type=1400 audit(1407319676.719:3): apparmor="STATUS" operation="profile_load" name="/usr/lib/NetworkManager/nm-dhcp-client.action" pid=516 comm="apparmor_parser"
Aug 6 07:07:58 cesarcostap2-To-be-filled-by-O-E-M kernel: [ 9.859930] type=1400 audit(1407319676.719:6): apparmor="STATUS" operation="profile_replace" name="/usr/lib/NetworkManager/nm-dhcp-client.action" pid=517 comm="apparmor_parser"
cesarcostap2@cesarcostap2-To-be-filled-by-O-E-M:~$