You can use network address translation (NAT) for traffic that goes through a VPN. This may be necessary, for example, if the private networks at either end of the VPN use the same private IP addresses.
We do not recommend 1-to-1 NAT to resolve an issue with sites that have overlapping IP addresses. 1-to-1 NAT introduces scalability and management challenges. Instead, we recommend that you change the IP addressing on one of the sites so the IP addresses do not overlap. You can configure secondary networks for this purpose. For more information, see Add a Secondary Network IP Address. However, if you cannot reconfigure IP addressing because you do not own one of the sites, you could consider 1-to-1 NAT to resolve the issue.
For more information, see: