DHCP through multiple routers

I am trying pass dhcp requests through 2 cisco routers.  Here's a rough look ... end user pc ---> router 1 ---> router 2---> DHCP Server.

I have the ip helper address set to my dhcp server on router 1 with GIAddress included to pick up the different scope.  Do I need to add the ip helper address on router 2 also?  Do I need to forward the requests received by router 2?    
InsightMediaAsked:
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grsteedCommented:
InsightMedia - Haven't hear back from you.

When you say they aren't pulling an IP from the DHCP server, are they getting a 169.254.x.x (APIPA) address? If so that means they didn't hear back from the DHCP server. You can confirm this by running ipconfig /all at the command prompt. If it isn't a 169.254.x.x address, what address does it get? Maybe it's a problem with the DHCP scope giving the wrong Default Gateway address.

Gary
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grsteedCommented:
You only need the ip helper-address on router 1.  

But you also need to make sure router 1 and router 2 know how to route between those to networks. For example, from the Client network you need to be able to ping the DHCP Server, and from the DHCP server, you need to be able to ping the Client Network.

You should also check the Routing/Default Gateway on the Server to make sure it knows about the client network, or the Default Gateway that it's using knows about it.

Cheers,

Gary
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InsightMediaAuthor Commented:
Right.  The routers are already in place passing data.  I can browse that subnet, the users can browse my subnet and so on.  The thing is that the machines on that subnet are not pulling an address.  The local subnet is x.x.1.x with the default gateway of x.x.1.1 (eth 0/0 on Router 1).  The end user subnet is x.x.70.x with a default gateway of x.x.70.1 (eth 0/0 on Router 2).

The default gateway for subnet 1 (router 1) obviously knows about the other subnet because its passing data there all the time.  I can ping any address on that subnet from the DHCP server.  The end users can ping the DHCP server.  I have a scope all set up & ready to pass out 70.1 addresses.  Additionally, the DHCP server is passing out addresses on the local subnet.

I'm just making sure here, but isn't the ip helper address assigned to ethernet0 port (x.x.70.1)?

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grsteedCommented:
> The end user subnet is x.x.70.x with a default gateway of x.x.70.1 (eth 0/0 on Router 2).

You diagram shows router 1 for the end user subnet.

> I'm just making sure here, but isn't the ip helper address assigned to ethernet0 port (x.x.70.1)?

If that's the interface that the end user subnet is connected to, that's correct.

Gary
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LANWorxCommented:
Hi
The ip-helper address should be the IP address of your DHCP server on the e0/0 interface of your router 2 (server end). The router 1 (user end) will receive the dhcp request broadcast, and then forward it to the IP address that you tell it to (via ip-helper). The DHCP server will look for a scope that matches the IP address of the router 1 interface that received the broadcast, so make sure you have a X.X.70.X scope ready. The response is routed back to the user end router and then back to the client via MAC address.

good luck
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InsightMediaAuthor Commented:
Apparently, the default gateway is kind of important (feeling stupid).  I mean, really - duh?!  I figured is was something simple.  I set the default gateway for the local subnet by mistake.  Thanks for your help, grsteed.
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grsteedCommented:
Glad you found it.

Happy to help.

Gary
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