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PXE not picking up DHCP address

Frank Ng
Advisor

PXE not picking up DHCP address

c7000 enc
465 blade
VC ethernet interconnect
VC Profile setup with nics assigned to the right network
VC uplink to the same network as the DHCP server

When server 465c boots up, I see the ...

Mar 20 02:16:30 dhcpserver dhcpd: DHCPDISCOVER from 00:17:a4:77:00:0a via eth0

Mar 20 02:16:30 dhcpserver dhcpd: DHCPOFFER on 10.x.x.102 to 00:17:a4:77:00:0a via eth0

and this repeats at least 10 times before I get the PXE-E51 "No DHCP or ProxyDHCP offer were received" error.

Basically, I never see the dhcp ack from the blade.

Everything has been done to make sure a successful pxe boot ...

Disabled spanning tree on the switch port that the vc interconnect is connected to.

pxe configured in the vc profile and on the right nic

pxe also setup in RSBU (though overwrites by VC)

BIOS have WOL turned off

pxe driver have WOL turned off

I don't know if this is VC specific. I'll be configuring the cisco interconnect tomorrow to test.

Anyone seen this before?

5 REPLIES
Frank Ng
Advisor

Re: PXE not picking up DHCP address

Just an update.

It looks like it is VC specific. I replaced the virtual connect ethernet modules with the cisco 3020s and the problem went away.

Anyone have any experience with virtual connect ethernet?

All the VC profiles were setup and pointing to the right network.
HEM_2
Honored Contributor

Re: PXE not picking up DHCP address

Frank:

That is strange because you are definitely seeing the DHCP Discover reaching the DHCP server, i.e. it's not zero reachability

What does your VC config look like? Do you have shared uplink sets? A mismatched config between VC shared uplink sets and maybe a static channel configured on the upstream switch could cause issues.

You might try simplifying the config on VC to a single network and 1 uplink to the rest of the world.
George Denyer_1
Frequent Advisor

Re: PXE not picking up DHCP address

Frank, did you ever find a solution for this?

I'm experiencing exactly the same problem, in fact with the same models of enclosure and servers. Same as you, I see the DISCOVER and OFFER packets but no ACK. If I substitute the VC Ethernet modules with Ethernet Pass-Thru modules everything works.

If you got an answer to your problem, please let me know. Thanks.

G. Denyer
Frank Ng
Advisor

Re: PXE not picking up DHCP address

When I posted that, it was our test unit. we ordered almost everything you can for the c-class enclosure and tested each piece. at the end, we decided we don't really need the functionalities of the virtual connect for our application farm.

it complicates our architecture and put more load on the deployment.

The VC idea is great, just that not everyone "need" it.

When we went production, we did without the VC piece.

Sorry, I couldn't help further.

-fng
George Denyer_1
Frequent Advisor

Re: PXE not picking up DHCP address

Ok, thanks, if I get an answer I'll post it here anyway.

G. Denyer