Netgate Discussion Forum
    • Categories
    • Recent
    • Tags
    • Popular
    • Users
    • Search
    • Register
    • Login

    IPsec with NAT between pfSense and Fortigate - no ping or access from both sides

    Scheduled Pinned Locked Moved IPsec
    2 Posts 2 Posters 770 Views
    Loading More Posts
    • Oldest to Newest
    • Newest to Oldest
    • Most Votes
    Reply
    • Reply as topic
    Log in to reply
    This topic has been deleted. Only users with topic management privileges can see it.
    • M
      marcos.lang
      last edited by

      We have an IPsec VPN tunnel with NAT between pfSense 2.3.4 and Fortigate up and running.

      The local networks are the same (overlapping), so we use NAT.

      pfSense is managed by us and Fortigate by a partner (who defined the tunnel configuration parameters).

      However, I cannot ping or access any features on both sides.

      I believe the problem is in P2, whose configuration is as follows (for example):

      pfSense
      Local Subnet: Network 10.0.0.0/21
      NAT Local Subnet: Address 172.140.50.2/32 (yes, public IP!)
      NAT Remote Subnet: Address 172.140.60.2/32

      For testing purposes, all traffic was opened in the IPsec interface at both ends.

      What can be missing or wrong?

      The use of public IP in NAT (I believe not)?
      The difference in size of Local "real" and NAT'ed networks?
      Should I use /24 on NAT'ed networks and create a 1:1 relation on both ends?
      Should I create a VIP with the NAT'ed IP of Local Subnet (172.140.50.2/32)?
      Should I create a static route for the NAT'ed IP of Remote Subnet (172.140.60.2/32)?

      Thanks in advance for your help.

      bepoB 1 Reply Last reply Reply Quote 0
      • bepoB
        bepo @marcos.lang
        last edited by

        @marcos-lang Could you please provide screenshots from your configuration and the ipsec status pages? Especially from SAD/SPD etc?

        The use of public IP in NAT (I believe not)? > This should work without problems.

        The difference in size of Local "real" and NAT'ed networks? > If you want to NAT your Local Network into a single ip you have to choose NAT/BINAT Type "Address" and NOT Network/32.

        Should I use /24 on NAT'ed networks and create a 1:1 relation on both ends? > No

        Should I create a VIP with the NAT'ed IP of Local Subnet (172.140.50.2/32)? > No

        Should I create a static route for the NAT'ed IP of Remote Subnet (172.140.60.2/32)? > No. Routing is ignored for IPSec

        Please use the thumbs up button if you received a helpful advice. Thank you!

        1 Reply Last reply Reply Quote 0
        • First post
          Last post
        Copyright 2025 Rubicon Communications LLC (Netgate). All rights reserved.