NAT Rule to work on internal network



  • Hello,

    I just received my fiber connection from my internet provider and there settings as follows:

    WAN: 172.17.X.X - VLAN 8XX

    LAN Subnet: 41.X.X.X

    I created the VLAN and made it the WAN interface and assigned the IP address and created the LAN with 41.X.X.X. After disabling the NAT and assign a local computer on the LAN interface within the IP range of the 41.X.X.X I can connect to the internet and get my full speed.

    However, my question is; I wanna create a local subnet with NAT to be able to use the internet, and I can't do so, any pointers?

    Note: I have to get out to the internet through 41.X.X.X

    Many thanks in advance.


  • LAYER 8 Global Moderator

    How big is this 41 block? / what? 29, 28?



  • 41.X.X.X/28, and that's a public IPs. I need to create an internal IP to use one of the public IPs.


  • LAYER 8 Global Moderator

    Well if the traffic is routed to you via a rfc1918 transit, you could sub that out into say 2 /29's and should be able to use one of the /29's as VIPs and then nat with those.



  • Could you explain that into more details please?


  • LAYER 8 Global Moderator

    Well split your /28 into 2 /29.. So for example

    41.0.0.0/28 = .1 to .14
    41.0.0.0/29 = .1 to .6 (lan IPs)
    41.0.0.8/29 = .9 to .14 (vip IPs)

    Use either of those as your network behind pfsense, and then use the other as VIP IPs that you nat with..

    Depends on how many IPs you need behind... You could also just use them all as VIPs and use everything behind on rfc1918.. Just because they routed the /28 to you doesn't mean you can't just use them all as VIPs on and do everything behind a nat.


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