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

    Second subnet on same OPT interface

    Scheduled Pinned Locked Moved HA/CARP/VIPs
    3 Posts 3 Posters 3.8k 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.
    • 2
      2qik
      last edited by

      Hello

      I have two pfSense boxes running 1.2.3.  We run one CARP IP for failover of the WAN interface which works great.
      Then I run another CARP VIP for failover of the OPT1 interface.  This also works great.
      However our provider has allocated us additional address space and it is a separate subnet.  I would like to run this on OPT1 still if possible.
      However I cannot setup a VIP with CARP due to there being no IP on that subnet.
      I thought I could get around it by creating another interface on the same physical LAN and setting an IP on each pfSense and then a CARP address.  However then we get issues with ARP as the same physical network is on two interfaces.

      Is there a way to make this work and to have failover still on the second subnet?
      I would rather not have to have a separate physical LAN just to cater for additional address space.

      I hear there is IP aliasing in v2.0 but that is still RC.

      Look forward to hearing your thoughts.

      1 Reply Last reply Reply Quote 0
      • marcellocM
        marcelloc
        last edited by

        You will need to configure your router to send this second subnet by another interface or configure both on same router interface using vlans(your switch must work with vlans too).

        Then, configure a OPT2 interface for these additional addresses.

        works fine for me.

        att,
        Marcello Coutinho

        Treinamentos de Elite: http://sys-squad.com

        Help a community developer! ;D

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

          If your ISP is routing that additional subnet to your OPT1 CARP VIP, then you need only add them as "other" type VIPs, not CARP VIPs. Then they can be used for NAT.

          If it's delivered directly, where the ISP gear expects you to have "real" IPs there, you'll need to upgrade to 2.0. Then you can make an IP alias VIP on each firewall in the new subnet, and then you can add CARP IPs for that subnet.

          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.