Multiple routes on LAN now I can't get DHCP addresses

[ISDPCMAN]

We recently added a high speed interent connection to a branch office that
used to get its internet access through a VPN connection to the main office.
Before we were able to use DHCP for this (DHCP was on an old 2000 server. Now
we've moved that to a 2003 server) we create a persistent static route so the
routers would work. Here's the layout:

New Gateway: 10.10.8.5
VPN router: 10.10.8.1
LAN subnet: 10.10.8.x / 24
VPN subnet: 10.10.9.x / 24

I used the Windows ROUTE comand (e.g. Route -p ADD 10.10.9.0 mask
255.255.255.0 10.10.8.1) to add a static route and changed the default
gateway from the .8.2 to .8.5 so they would use the new high speed broadband
firewall as their default outbound gateway.

I changed the addresses on the PC's to be static, added the .8.5 default
gateway and things worked fine. DNS and VPN traffice resolved to the .9.x
subnet, all internet traffic went out the .8.5 firewall and speed was great.

My next step was to move DHCP from the 2000 server to 2003 to use the DHCP
Option 249 (Classless Route) so I can use DHCP again and remove these static
IP settings.

In Windows Server 2003 I added the DHCP option 249 (classless route) to
enable this configuration dynamically.

I went to one of the PC's on the .8.x subnet and changed from static IP to
DHCP. I rebooted and the PC was no longer able to contact the DHCP server. I
got an APIPA address

What did I miss here? I need this to work dynamically on this branch office
subnet so as we add PC's they'll work as planned.

 

[Robert L. \(MS-MVP\)]

Posting the routing table here may help.

--
Bob Lin, MS-MVP, MCSE & CNE
Networking, Internet, Routing, VPN Troubleshooting on
http://www.ChicagoTech.net
How to Setup Windows, Network, VPN & Remote Access on
http://www.HowToNetworking.com

 

[ISDPCMAN]

There's not much to show.
Active Routes:
Network Destination Netmask Gateway Interface Metric
0.0.0.0 0.0.0.0 10.10.8.5 10.10.8.99 20
127.0.0.0 255.0.0.0 127.0.0.1 127.0.0.1 1
10.10.9.0 255.255.255.0 10.10.8.1 10.10.8.99 1
10.10.8.0 255.255.255.0 10.10.8.99 10.10.8.99 20
10.10.8.99 255.255.255.255 127.0.0.1 127.0.0.1 20
10.10.8.255 255.255.255.255 10.10.8.99 10.10.8.99 20
224.0.0.0 240.0.0.0 10.10.8.99 10.10.8.99 20
255.255.255.255 255.255.255.255 10.10.8.99 10.10.8.99 1
Default Gateway: 10.10.8.5
===========================================================================
Persistent Routes:
Network Address Netmask Gateway Address Metric
10.10.9.0 255.255.255.0 10.10.8.1 1

I had to change the scheme to static IP and routes because with the default
gateway set to 10.10.8.5 I cannot get a DHCP address. I suspect at this point
I may need to create a static route on the .8.5 gateway as it doesn't seem to
be talking to the .8.1 gateway.

How does windows know what router to use to get a DHCP address? DHCP
passthrough is enabled on the .8.1 VPN router so I thought it would get an
address from our server at the main office but it's not happening and I Have
to make all the systems static to get this to work. That's not the way I
would prefer this to work.

How do I configure this setup to use DHCP properly?