Multiple devices same IP block



  • Not sure I'm asking this on the correct forum, forgive me if I posted in the wrong place.

    We are using PFsense 1.2.3 with static IP's from our ISP.  Everything is working correctly with the exception of the Wireless which we are not sure how to setup.  For security reasons we are not allowed to have WiFi inside the network, nor can we route it through the firewall.

    Cable Modem Static IP's:      62.114.15.29/28  gateway: 62.114.15.17    (SAMPLE IP's NOT REAL)

    PFsense WAN configuration:  62.114.15.18/28   gateway: 62.114.15.17
    WIFI Linksys Router:            62.114.15.29/28   gateway: 62.114.15.17

    We plugged the WiFi router into the cable modem along with PFsense WAN and assigned ONE of the IP's in the block that isn't used for anything on PFsense.  However, the IP is clearly configured on PFsense WAN because it is in the same block.

    Our question is what will this screwup or are we causing some crazy packet routing?  I always understood you couldn't do this, but not sure how to solve my problem.

    As an FYI, the cable modem is in bridge mode.  It doesn't have any private IP addresses.

    THANK YOU in advance for any input.



  • Did you actually create VIPs in pfSense for every IP in the block?  If not, your pfSense box only has xxx.xxx.xxx.18.

    BTW, I'd strongly suggest you edit your post to only include the last octet of those IPs…



  • Now that I think about it you are correct.  I created VIPs on PFsense for every address except the 62.114.15.29/28 address that I use on the WiFi.  So based on what your saying.  I guess I don't have an issue.

    As an FYI I did end up placing a check on the "suppress ARP msg when interfaces share physical network".

    I was thinking I may have been creating a packet storm or whatever its called but I'm guessing I'm ok.

    Jason, THANK YOU for your response and assistance.


Log in to reply