I have a L2TP connection from A&A.  Tunnel comes up fine and I can see the public IP on my end of the tunnel on traceroute etc.  

I also have a /29 block on the same connection.  I have set this up on the routed subnet LAN and given the router an address on that block.

My problem is that incoming connections to the server on the block appear to come from the router's address, not from the originating IP address.  The connections actually do work just fine and I can access the services on the server but not being able to determine where the connection really originates from is a problem as you can imagine for example email filtering.

Its like the router is applying some sort of address translation or port forwarding between the tunnel and the routed LAN.

I've set up other /29 blocks as routed LAN's but those have been carried over the WAN DSL interface.  Is there some limitation when the block comes over a VPN or some setting I need to apply?

Thanks.