PXE Booting With VLans

[athar_iqbal]

Hi Guys,

I need help. I have a network where we install OS through PXE boot. I was trying to configure my VLANS. I have five VLANS. All servers are in one VLAN and all the other benches which broadcast in their respective VLAN. I am using windows 2003 DHCP server which is also a WDS server. Once I fired up the switch and client to boot up. Client got the DHCP ID and GIVES me PXE E55. I am not able to resolve the issue.

[ohassairi]

we are not familiar with PXE.

can you tell us what is this PXE E55? is it an error? what does it mean?

[gpulos]

Your PXE-E55 is telling you that the system cannot communicate with the dhcp server.

Since you split up the systems into vlans, with all servers in one vlan, you've now created a block between the systems being able to send BOOTP/DHCP requests to the dhcp server.

DHCP clients use a broadcast to request addresses from dhcp servers. Since you split the dhcp server into a different vlan than the other systems, the dhcp broadcast request cannot reach the dhcp server.

You need to enable bootp/dhcp forwarding so the broadcast can be sent from one vlan to another.

This will require routing be enabled between the vlans if it is not already.

Once routing is enabled between the vlans, you'll need to put the 'ip helper-address x.x.x.x' command on the router interfaces that need to forward the dhcp requests.

(the x.x.x.x is the ip address of the dhcp server)

Please see the following links for more information on bootp/dhcp forwarding and the 'ip helper-address' command:

understanding dhcp/troubleshooting:

http://www.cisco.com/en/US/tech/tk648/tk361/technologies_tech_note09186a00800f0804.shtml#scenarios

ip helper-address command:

http://www.cisco.com/en/US/docs/ios/12_0/np1/command/reference/1ripadr.html#wp1018606