Multiple ISP routers with the same IP address



  • Hello everyone!
    I need to load balance an office with multiple connections.
    The problem is that I have 3 routers and they have hardcoded the same IP address and I cannot be changed (we called the ISP with no luck).

    My situation is
    ISP 1: 192.168.15.1/24
    ISP 2: 192.168.15.1/24
    ISP 3: 192.168.15.1/24
    and my pfsense box.

    Is there a way with pfsense to do multiple wan with this scenario? I don't mind using tons of VLAN, VIP or something else.

    Thanks!


  • LAYER 8 Netgate

    @horace:

    The problem is that I have 3 routers and they have hardcoded the same IP address and I cannot be changed (we called the ISP with no luck).

    Get another ISP.



  • multiple ISP routers from same ISP or mutilpe ISPs?

    Anyway, if protocols you intend to use support double NAT, you could easily attach one device behind here router that you NAT your hard-coded address into something unique. Then attach these devices to pfSense and define the addresses as gateway pointing to each ISP.

    ISP1 => router => 192.168.1.1 => router => 192.168.2.1
    ISP1 => router => 192.168.1.1 => router => 192.168.2.2
    ISP1 => router => 192.168.1.1 => router => 192.168.2.3

    attach pfSense WAN at 192.168.2.4 (all IPs are examples only) and your done, at the cost of double NAT.



  • I can't change ISP now and I don't have any other router. I have only 3 ISP routers (from the same provider) and my pfsense box

    ISP router 1 with IP 192.168.15.1 <–> | -------------- |
    ISP router 2 with IP 192.168.15.1 <--> | pfsense box  |
    ISP router 3 with IP 192.168.15.1 <--> | -------------- |



  • So you're stuck with one single gateway isn't it?



  • cant be done. you are gonna have to change isp's or add a double NAT mess.

    are you sure you can't modify the routers or do pppoe ?


  • Banned

    I think it's pretty obvious this absolutely CANNOT work, pfSense or not, without doing another layer of NAT in between. Not exactly sure what's still being discussed here? You cannot have 3 boxes with the same IP and expect to the router to be able to distinguish among them.  ::)


  • LAYER 8 Netgate

    @heper:

    cant be done. you are gonna have to change isp's or add a double NAT mess.

    Or convince the ISP they're being donkeys.



  • @doktornotor:

    I think it's pretty obvious this absolutely CANNOT work, pfSense or not, without doing another layer of NAT in between. Not exactly sure what's still being discussed here? You cannot have 3 boxes with the same IP and expect to the router to be able to distinguish among them.  ::)

    Someone pointed me out can you do that with RouterOS with something like this

    add destination=0.0.0.0/0 gateway=192.168.1.1%ether1 routing-mark=Adsl1
    add destination=0.0.0.0/0 gateway=192.168.1.1%ether2 routing-mark=Adsl2

    This is why I was asking.

    Btw I solved using a super ugly double NAT with multiple routers until we change ISP.


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