Implementing DHCP while migrating networks

[hambo12]

Quick question:

We have our current network as 203.xxx.xxx.xxx.
All of our computers and servers are located here.

We have since setup a VLAN on our routers with the 10.0.0.x range. Our DC is located on the 203 range, but I would like it to use DHCP to assign IP's to the 10.0.0.x range. Is this possible?

I can get DHCP working for the 203 range, but it seems something is stopping the 10 range from having IP's assigned. I have setup the scope under a superscope.

Could this be something to do with our router config that blocks the broadcast messages??

 

[theravager]

assign a ip helper address on your vlans pointing to the dhcp server

 

[cajuntank]

Have you enabled the ip helper-address statement on your vlan interface pointing to the DHCP server so that it can relay DHCP?

Also, you have computers assigned on your network with public network addresses?

 

[hambo12]

I have setup ip helper-address on the VLAN, as well as enabled dhcp-relay. Still have nothing...

Yes, the existing IP range are public addresses...

Any thing else I could be missing??

 

[theravager]

I would be doing some network sniffing to see what is going wrong.

You don't need a superscope either.

 

[hambo12]

OK have used wireshark to find out what is happening in between.

I am getting the following messages when I enable DHCP on my laptop:

DHCP Discover
DHCP Offer
DHCP Request
DHCP NAK
DHCP ACK

And these messages repeat over and over.

Also, in my local event viewer I am getting the following error rapeating:

The IP address lease 0.0.0.0 for the Network Card with network address has been denied by the DHCP server (The DHCP Server sent a DHCPNACK message).

(I have deleted IP address and network address fro security reasons)

I have done a release and renew with no luck...

 

[theravager]

are those requests coming from the server ip in wireshark?

Normally you only get a nak if there is something funny in the network config or the client has switched subnets.

 

[IRudebwoy]

Can your DHCP servers reach the 10.X.X.X net? Try pinging the gateway IP's on the 10.X.X.X net.

If it can't you've got a routing issue. The clients may be able reach the server. Maybe the server can't or doesn't know how to reach the clients.

 

[hambo12]

I can ping servers/gateways/switches from both networks.

Below I have expanded each message with the source and destination:

Source: 0.0.0.0 Destination: 255.255.255.255 DHCP Discover

Source: (DHCP Server) Destination: 10.0.0.89 (my static IP) DHCP Offer

Source: 0.0.0.0 Destination: 255.255.255.255 DHCP Request

Source: (DHCP Server) Destination: 255.255.255.255 DHCP NAK

Source: (DHCP Server) Destination: 10.0.0.89 (My static IP) DHCP ACK

So it looks as though the server is trying to assign an IP, and the message is being recieved??? Any ideas??

 

[hambo12]

any thoughts??

 

[IRudebwoy]

Put wireshark on a client to see if the DHCPACK's are making it back to the clients.

Is there any kind of firewall between the 203 and 10 nets? If 203 is public, I would expect so.

What are the times of the above log entries?

Try a trace route on 10.0.0.89 to see where the server gets routed.