Netopia 3346N-ENT User Guide (en)

Multiple Network Address Translation   4-31
A restriction
Since both the router and the passthrough host will use same IP address, new sessions that conflict with 
existing sessions will be rejected by the router. For example, suppose you are a teleworker using an IPSec 
tunnel from the router and from the passthrough host. Both tunnels go to the same remote endpoint, such as 
the VPN access concentrator at your employer’s office. In this case, the first one to star t the IPSec traffic will 
be allowed; the second one – since, from the WAN it's indistinguishable – will fail.