The remote peer (your laptop) would have a dynamically allocated Internet facing (public) address from the network that it will find itself in at the time it starts initiating a connection.
However, it will also require a private address, ideally different to the private address space used by Netvanta's LAN. So, if say your Netvanta's LAN is using 10.10.10.0/24, you can set up a pool within the 172.16.0.0 - 172.31.255.255 or 192.168.0.0 - 192.168.255.255 private address space. For example, you can set a range like 172.16.1.1-172.16.1.255
For a guide using the Netvanta GUI to set up your VPN connection, have a look at this: https://supportforums.adtran.com/docs/DOC-2907
For a guide to configure the Shrewsoft client, you can use this: https://supportforums.adtran.com/docs/DOC-2268
Please ask again if the above is not clear.
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