zanub
Can you confirm that the ip helper-address is correctly configured with the address of the DHCP server? And can you confirm that there is IP connectivity between your L3 switch to which you connect and the DHCP server (ping to the server from the L3 switch is the easy way to demonstrate this)? And can you confirm that the DHCP server has a correct scope configured for the subnet on the interface of the L3 switch to which you connect?
In my experience these are the 3 most common reasons why end stations fail to receive addresses from DHCP servers. If you confirm that all 3 of these are correct then we will look for other explanations and solutions to the problem.
I would not expect that your provider would need to config ip helper-address on their MPLS routers since your L3 switch should just generate a unicast packet to the server address. The MPLS routers just need to forward it. You might want to check with the provider and verify that their routers would forward this traffic (check to make sure that they do not have access lists or other filtering that would deny it).
HTH
Rick
HTH
Rick
