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

    CARP with only one available WAN ip address

    Scheduled Pinned Locked Moved HA/CARP/VIPs
    2 Posts 2 Posters 2.2k 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.
    • I
      itsbruce
      last edited by

      We have a /30 netblock to manage the link between our ISP's router and us, with a larger netblock routable via our systems.  So of the two usable ip addresses on the 30 network, the lower address is used by their router and is our gateway to the Net, while the higher address is used by our kit and is the gateway to our larger DMZ netblock.

      Now, I'd like to use a pair of pfsense boxes to link all this together, but I can't create the VIP because the web interface will not allow me to create a VIP where there is no matching subnet already configured on an interface.

      Is there a practical way for me to get around that restriction, or am I just going to have to put in something else to manage the initial link?

      Using the latest stable version, btw.

      1 Reply Last reply Reply Quote 0
      • jimpJ
        jimp Rebel Alliance Developer Netgate
        last edited by

        There is no currently supported/working way to do CARP on WAN with a single IP address. You need at least three: One for each box, and the shared CARP VIP.

        This may change in the future if carpdev ever makes its way in. From what I understand that lets the routers have IPs in a separate subnet from the shared IP. But for now, with only a /30 on WAN, something will have to talk to that.

        In doing so, however, you lose the high availability that CARP gains you and you're back to a single point of failure.

        Remember: Upvote with the 👍 button for any user/post you find to be helpful, informative, or deserving of recognition!

        Need help fast? Netgate Global Support!

        Do not Chat/PM for help!

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