CARP and NAT question

[Matthew Grooms]

On 10/8/2019 10:58 AM, Julien Cigar wrote:
> On Tue, Oct 08, 2019 at 10:20:34AM -0500, Matthew Grooms wrote:
>> Hi Julien,
> Hi Matthew,
>
>> It's not clear why you are trying to assign multiple carp IP address to
>> two different interfaces from within the same IP subnet. Are you trying
>> to fail over a 2nd carp address or are you trying to improve
>> throughput/redundancy? If you just want to fail over a 2nd carp address,
>> assign a 2nd alias to your first interface. If your trying to improve
>> throughput/redundancy, assign both interfaces to a lagg and build your
>> carp interfaces on top of that instead.
>>
> Currently outbound traffic from $net1 and $net2 (two private networks)
> pass through the same network interface (igb0) (as you can see in (1)
> in my previous post) on the router. I'd like to prevent that
> $net2 saturates the interface and slow down traffic from $net1 (which is
> more important). I could lagg and build CARP on top of that but it
> wouldn't prevent $net2 to saturate the interface (unless I'm plugin ALTQ
> of course, which I'd like to avoid).

Well, I'm not sure how well it will work but I think what you are 
looking for is the route-to pf rule option. You can specify that certain 
traffic be transmitted via a specific network interface to a specific 
next hop. However, I believe you'll need to match traffic as it's 
received on the internal interface, ie. before the kernel determines the 
egress interface.

table internal_networks { $net1, $net2 }
pass in on $internal_interface route-to( igb0 $default_gw ) from $net1 
to !<internal_networks>
pass in on $internal_interface route-to( igb1 $default_gw ) from $net2 
to !<internal_networks>

Hope this helps,

-Matthew