PXE wont get a DHCP IP address through Virtual Connect

[George Denyer_1]

Hi,

We're setting up a C7000 enclosure with BL465c servers and virtual connect. PXE never gets an IP address from DHCP and gives error PXE-E51: "No DHCP or DHCP Proxy Offers received", but a packet capture shows that for every DHCPDISCOVER packet from the blade there is a corresponding DHCPOFFER packet from the DHCP Server but there never is a DHCPREQUEST packet from the blade as there should be. This only happens with Virtual Connect, if I substitute the VC modules with pass-thru modules everything works just fine.

Has anybody else seen something similar? Any thoughts?

Thanks,

GD

[HEM_2]

how is Virtual Connect set up? What networks do you have defined and what uplinks are you using?

try simplifying your VC network that the PXE NIC is connected to down to a single uplink for troubleshooting.

DHCP Server is on the same subnet as the PXE client or are you using a relay agent/helper?

VC FW 1.22?

[George Denyer_1]

Hi HEM, thanks for your answer.

Virtual Connect is set up with a single network and a shared uplink set with 8 uplinks, 4 from each module, but for troubleshooting I disabled all but one of the uplinks.

DHCP is on the same subnet as the PXE client, in the same server as RDP.

VC FW is 1.21.

[HEM_2 · Accepted solution]

OK, a shared uplink set with 1 network defined?

What VLAN ID do you have set for the network in the shared uplink set?

Do you have the Native checkbox checked?

How is the upstream switch configured? Is it configured as a dot1q trunk (tagged) or as an access port (untagged)?

If it is a Cisco dot1q trunk, what is the native VLAN set for?

I suspect a Native VLAN mismatch to be causing your problem.

[Jimmy Vance]

In Virtual Connect Manager under

server profiles
- assigned server profiles
-

Look at your defined Ethernet networks. Make sure the Port you have attached to the Network Name you created shows a green OK check mark, and that PXE is enabled on that port.

[George Denyer_1]

HEM, you were right again. The ports on the switch were configured as access ports, now they are configured as dot1q trunk ports and DHCP is working.

Thanks HEM and Jimmy.

GD

[George Denyer_1]

The upstream switch was misconfigured, the ports Virtual Connect was connected to were configured as access ports instead of dot1q trunk ports. Fixing this solved the problem.