I found s.th. else, that is dhclient, which reports:
[root@localhost ~]# dhclient
Internet Systems Consortium DHCP Client V3.0.1
Copyright 2004 Internet Systems Consortium.
All rights reserved.
For info, please visit
http://www.isc.org/products/DHCP
sit0: unknown hardware address type 776
sit0: unknown hardware address type 776
Listening on LPF/sit0/
Sending on LPF/sit0/
Listening on LPF/eth0/00:c0:9f:42:33:e6
Sending on LPF/eth0/00:c0:9f:42:33:e6
Listening on LPF/lo/
Sending on LPF/lo/
Sending on Socket/fallback
DHCPDISCOVER on sit0 to 255.255.255.255 port 67 interval 7
DHCPREQUEST on eth0 to 255.255.255.255 port 67
DHCPDISCOVER on lo to 255.255.255.255 port 67 interval 8
DHCPREQUEST on eth0 to 255.255.255.255 port 67
DHCPDISCOVER on sit0 to 255.255.255.255 port 67 interval 15
DHCPDISCOVER on lo to 255.255.255.255 port 67 interval 8
DHCPREQUEST on eth0 to 255.255.255.255 port 67
DHCPDISCOVER on lo to 255.255.255.255 port 67 interval 7
DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 4
DHCPDISCOVER on sit0 to 255.255.255.255 port 67 interval 15
DHCPDISCOVER on lo to 255.255.255.255 port 67 interval 8
DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 8
DHCPDISCOVER on lo to 255.255.255.255 port 67 interval 10
DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 10
DHCPDISCOVER on sit0 to 255.255.255.255 port 67 interval 21
DHCPDISCOVER on lo to 255.255.255.255 port 67 interval 11
DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 11
DHCPDISCOVER on lo to 255.255.255.255 port 67 interval 9
DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 14
DHCPDISCOVER on sit0 to 255.255.255.255 port 67 interval 3
No DHCPOFFERS received.
No working leases in persistent database - sleeping.