Need help with IPSEC with overlapping subnets/How to use BINAT/NAT options

  • Hello,

    I never used PFSense 2.1 before and yesterday I had to upgrade my 2.03 to 2.1 in order to be able to use NAT on an IPSEC site to site VPN.

    I currently need to connect two different sites, one using 10.1.x.x/16 subnet and the other on 10.x.x.x subnet. I tried to search a lot about how to use the new NAT options available on the phase II part of the IPSEC options, but could not find a tutorial or something.

    Does anyone have a tutorial on that ?

    Does it need more firewall rules than the usual IPSEC rules ?

    Thanks in advance,


  • Rebel Alliance Developer Netgate

    There isn't much to it, really. Just set the NAT subnet to be whatever you want your side to appear as when the packets reach the remote site.

    Note that NAT+IPsec in this way only helps if your LAN subnet conflicts with a remote network that you aren't trying to reach directly. It won't let you reach two identical remote networks (they would need to do NAT on that side)

    Firewall rules on IPsec tab still refer to your local/LAN IPs as the destination.

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