On Tue, May 28, 2013 at 3:29 AM, Rainer Duffner <rainer@ultra-secure.de> wrote:

May 27 16:21:13 cobbler dhcpd: DHCPACK on 10.38.111.143 to
00:0c:29:a1:f5:b6 via eth1
May 27 16:21:13 cobbler dhcpd: Abandoning IP address 10.38.111.143:
declined.
May 27 16:21:13 cobbler dhcpd: DHCPDECLINE of 10.38.111.143 from
00:0c:29:a1:f5:b6 via eth1: abandoned
May 27 16:21:13 cobbler dhcpd: DHCPDISCOVER from 00:0c:29:a1:f5:b6 via
eth1
May 27 16:21:14 cobbler dhcpd: DHCPOFFER on 10.38.111.144 to
00:0c:29:a1:f5:b6 via eth1
May 27 16:21:14 cobbler dhcpd: DHCPREQUEST for 10.38.111.144
(10.38.111.19) from 00:0c:29:a1:f5:b6 via eth1
May 27 16:21:14 cobbler dhcpd: DHCPACK on 10.38.111.144 to
00:0c:29:a1:f5:b6 via eth1
May 27 16:21:14 cobbler dhcpd: Abandoning IP address 10.38.111.144:
declined.
May 27 16:21:14 cobbler dhcpd: DHCPDECLINE of 10.38.111.144 from
00:0c:29:a1:f5:b6 via eth1: abandoned

10.38 is my pxe-network, of course and ...b6 is the MAC of the
ubuntu-server to be installed.
Using the shell on ALT-F2, I can see that the server has basically
gobbled up all the IPs from that scope as "secondary" IPs.

That seems like more of a dhcpd/addressing issue than anything. From http://www.ietf.org/rfc/rfc2131.txt:

DHCPDECLINE  -  Client to server indicating network address is already in use.

If the client detects that the address is already in use (e.g., through the use of ARP), the client MUST send a DHCPDECLINE message to the server and restarts the configuration process.