[CentOS] Route traffic through private IP for only certain hosts

[Gordon Messmer]

Thanks for providing a lot of information.  My first guess is that the 
remote hosts you're trying to reach don't have the routes that they 
require to use the IPSec tunnel.  You demonstrated that server 2 has the 
route it needs to reach the remote network, and that server 1 appears to 
be routing those packets properly.  All of the same setup has to exist 
on the other side.