DHCP not handing IP to KVM in PXE boot
 

Hello,

I've been battling this issue for a couple days and figure I'd check in the forums to see if anyone has encountered this problem. My setup is as follows:

I have a server with 2 NIC ports. One is attached to the network I connect and manage the linux box from and the other is attached to a network that has a working DHCP running on it. I have verified the DHCP is setup correctly and does handout IPs to other boxes and the server receives an IP as well. I am running Fedora 11 i686 (2.6.29.6-217.2.8). I followed the instructions on the following site to setup a bridge on the port attached to my DHCP (http://www.linux-kvm.com/content/usi...g-virt-manager).

The bridge does show up in my list of Shared physical devices, and I have it added to my VM. I still do no receive an IP address on boot.

Any help or suggestions would be most appreciated. Also if you need any further information I would be happy to provide it.

-Dave

I've done some troubleshooting with Wireshark. I put Wireshark on the Fedora 11 physical machine running Qemu. When I activate the VM the following is the packet capture on the NIC port that the VM is bridged to: (sorry for the format, but it was the most readable I could export from Wireshark. The on the DHCP packets the first IP is the Source and the second is the Destination)

<packet>
<section>13</section>
<section>23.851330</section>
<section>0.0.0.0</section>
<section>255.255.255.255</section>
<section>DHCP</section>
<section>DHCP Discover - Transaction ID 0x89cfee</section>
</packet>

<packet>
<section>14</section>
<section>23.851906</section>
<section>10.51.13.1</section>
<section>255.255.255.255</section>
<section>DHCP</section>
<section>DHCP Offer - Transaction ID 0x89cfee</section>
</packet>

<packet>
<section>15</section>
<section>24.036300</section>
<section>Cisco_c3:28:0d</section>
<section>Spanning-tree-(for-bridges)_00</section>
<section>STP</section>
<section>Conf. Root = 32768/0/00:d0:58:c3:28:0c Cost = 0 Port = 0x801a</section>
</packet>

<packet>
<section>16</section>
<section>26.040940</section>
<section>Cisco_c3:28:0d</section>
<section>Spanning-tree-(for-bridges)_00</section>
<section>STP</section>
<section>Conf. Root = 32768/0/00:d0:58:c3:28:0c Cost = 0 Port = 0x801a</section>
</packet>

<packet>
<section>17</section>
<section>28.042352</section>
<section>Cisco_c3:28:0d</section>
<section>Spanning-tree-(for-bridges)_00</section>
<section>STP</section>
<section>Conf. Root = 32768/0/00:d0:58:c3:28:0c Cost = 0 Port = 0x801a</section>
</packet>

<packet>
<section>18</section>
<section>30.045431</section>
<section>Cisco_c3:28:0d</section>
<section>Spanning-tree-(for-bridges)_00</section>
<section>STP</section>
<section>Conf. Root = 32768/0/00:d0:58:c3:28:0c Cost = 0 Port = 0x801a</section>
</packet>

<packet>
<section>19</section>
<section>32.051334</section>
<section>Cisco_c3:28:0d</section>
<section>Spanning-tree-(for-bridges)_00</section>
<section>STP</section>
<section>Conf. Root = 32768/0/00:d0:58:c3:28:0c Cost = 0 Port = 0x801a</section>
</packet>

<packet>
<section>20</section>
<section>34.054197</section>
<section>Cisco_c3:28:0d</section>
<section>Spanning-tree-(for-bridges)_00</section>
<section>STP</section>
<section>Conf. Root = 32768/0/00:d0:58:c3:28:0c Cost = 0 Port = 0x801a</section>
</packet>

<packet>
<section>21</section>
<section>35.610415</section>
<section>Cisco_c3:28:0d</section>
<section>CDP/VTP/DTP/PAgP/UDLD</section>
<section>CDP</section>
<section>Device ID: R24Switch1 Port ID: FastEthernet0/13 </section>
</packet>

<packet>
<section>22</section>
<section>36.056490</section>
<section>Cisco_c3:28:0d</section>
<section>Spanning-tree-(for-bridges)_00</section>
<section>STP</section>
<section>Conf. Root = 32768/0/00:d0:58:c3:28:0c Cost = 0 Port = 0x801a</section>
</packet>

<packet>
<section>23</section>
<section>38.058492</section>
<section>Cisco_c3:28:0d</section>
<section>Spanning-tree-(for-bridges)_00</section>
<section>STP</section>
<section>Conf. Root = 32768/0/00:d0:58:c3:28:0c Cost = 0 Port = 0x801a</section>
</packet>

<packet>
<section>24</section>
<section>40.060486</section>
<section>Cisco_c3:28:0d</section>
<section>Spanning-tree-(for-bridges)_00</section>
<section>STP</section>
<section>Conf. Root = 32768/0/00:d0:58:c3:28:0c Cost = 0 Port = 0x801a</section>
</packet>

<packet>
<section>25</section>
<section>40.647446</section>
<section>10.51.13.3</section>
<section>255.255.255.255</section>
<section>DHCP</section>
<section>DHCP Request - Transaction ID 0x89cfee</section>
</packet>

<packet>
<section>26</section>
<section>40.662462</section>
<section>10.51.13.1</section>
<section>255.255.255.255</section>
<section>DHCP</section>
<section>DHCP ACK - Transaction ID 0x89cfee</section>
</packet>

<packet>
<section>27</section>
<section>42.063500</section>
<section>Cisco_c3:28:0d</section>
<section>Spanning-tree-(for-bridges)_00</section>
<section>STP</section>
<section>Conf. Root = 32768/0/00:d0:58:c3:28:0c Cost = 0 Port = 0x801a</section>
</packet>

<packet>
<section>28</section>
<section>44.066533</section>
<section>Cisco_c3:28:0d</section>
<section>Spanning-tree-(for-bridges)_00</section>
<section>STP</section>
<section>Conf. Root = 32768/0/00:d0:58:c3:28:0c Cost = 0 Port = 0x801a</section>
</packet>

<packet>
<section>29</section>
<section>46.069544</section>
<section>Cisco_c3:28:0d</section>
<section>Spanning-tree-(for-bridges)_00</section>
<section>STP</section>
<section>Conf. Root = 32768/0/00:d0:58:c3:28:0c Cost = 0 Port = 0x801a</section>
</packet>

<packet>
<section>30</section>
<section>48.072575</section>
<section>Cisco_c3:28:0d</section>
<section>Spanning-tree-(for-bridges)_00</section>
<section>STP</section>
<section>Conf. Root = 32768/0/00:d0:58:c3:28:0c Cost = 0 Port = 0x801a</section>
</packet>

<packet>
<section>31</section>
<section>50.075590</section>
<section>Cisco_c3:28:0d</section>
<section>Spanning-tree-(for-bridges)_00</section>
<section>STP</section>
<section>Conf. Root = 32768/0/00:d0:58:c3:28:0c Cost = 0 Port = 0x801a</section>
</packet>

<packet>
<section>32</section>
<section>50.807838</section>
<section>10.51.13.3</section>
<section>255.255.255.255</section>
<section>DHCP</section>
<section>DHCP Request - Transaction ID 0x89cfee</section>
</packet>

<packet>
<section>33</section>
<section>50.808703</section>
<section>10.51.13.1</section>
<section>255.255.255.255</section>
<section>DHCP</section>
<section>DHCP ACK - Transaction ID 0x89cfee</section>
</packet>


So as you can see in the packet capture, the DHCP does seem to deliver an IP address, but the VM does not show it in the prompt. It will continue to idle, seemingly waiting for the IP assignment. I ran a packet capture on the DHCP/PXE server when it ran the PXE boot on a physical machine and right after the IP address is assigned, there is a TFTP read request packet send out from the client to the PXE server. This read request never occurs on the VM as you can see in the packet capture.

Any help with this issue would be very much appreciated.

-Dave

did you ever get an answer?
 

I've been researching the same thing or something very similar. On non-pxe booting systems it assigns IPs just fine but I never see a dhcprequest on the pxe boots. This happens both with VMs and physical machines.