Multi WAN and 1:1 NAT

  • Hi Guys,

    Currently we have a x1 PFsense with Multi WAN and several Public IPs are NATed 1:1 for several Webservers for Public to Access. Since there's a single point of failure (Which is only one PFsense), we are looking to High Availability/Failover our Multi WAN along with it 1:1 NAT, is there any (if there are any) guides you can provide in doing so... I am familiar with Multi WAN failover but only for Outbound NAT (basically continuous Internet access for Internal clients), However we are looking if its possible to failover when you have an Inbound access from the public (which is the Client Facing Webservers).

    Appreciate your assistance and feedback to this topic.

  • LAYER 8 Netgate


    You generally need three WAN addresses. One for each node's interface and one for the CARP VIP. The CARP VIP swings between the primary and secondary nodes based on which one is the master.

    Additional IP addresses can ride on the CARP VIP and swing with it.

    So if the address being connected to from the outside then into 1:1 NAT is a CARP VIP or an address riding on a CARP VIP, it will be reachable on whatever node is active.

  • Hi @Derelict,

    Appreciate your response mate, quick points to ask though.
    So essentially, if we wanted this implementation to be successful or work, we needed more WAN IP addresses (Public IP)?
    As currently we have, ex. 3 ISP, each ISP provided us 5 Public IPs and these IP are already used for our 1:1 NAT/portforward..


  • LAYER 8 Netgate

    You really want an address for each interface for management of the nodes plus as many addresses as you need for services provided that can swing between them.

  • @Derelict hmmm, so WAN Addresses would be my roadblock/issue then, as web services are already 1:1 NATed, and my ISP can no longer provide additional WAN Addresses (Public IP) :(

  • LAYER 8 Netgate

    Pretty much comes down to usable subnet addresses -3 so a /29 on the interface has 3 addresses usable for HA services, a /28 has 11, /27 27, etc.

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