Assigning same ip address to different interfaces with different FIBs

[alan somers]

What you described doesn't work in FreeBSD, and there's even an open bug
for it.  But as Julian described, you should see if VIMAGE will work for
you.
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=189088

-Alan

On Wed, Apr 20, 2016 at 4:19 AM, Julian Elischer <julian at freebsd.org> wrote:

> On 20/04/2016 5:58 PM, M. V. via freebsd-net wrote:
>
>> Hello guys,
>> I have a problem with having multiple FIBs in FreeBSD-9.2. I've already
>> setup 4 FIBs in kernel, and everything is OK. I assigned each interface to
>> one FIB and I can add routes to any of FIBs I want, and everything works
>> fine.But my problem is, I want to assign same IP address to multiple
>> interfaces. for example:
>> interface em1 (in FIB-1) : 100.100.100.1/24interface em2 (in FIB-2) :
>> 100.100.100.1/24
>> this should work, bacause I want each FIB's interfaces and routes to be
>> completely separate from other FIBs' interfaces and routes. for this I do:#
>> sysctl net.add_addr_allfibs = 0
>>
> I think you are using the wrong tool to do this job.
> Fibs will "kind-of" allow you to do some of this but all fibs still 'see'
> all interfaces, Even if you don't set routes to them.
> What you want is VIMAGE/VNET
> Even though we've made vnet a characteristic of a jail (it wasn't always),
> you can still use it in the way you want if done right.
> Write a "how-to" when you've got it worked out :-)
>
>
> # ifconfig em1 fib 1# ifconfig em2 fib 2# setfib 1 ifconfig em1
>> 100.100.100.1/24# setfib 2 ifconfig em2 100.100.100.1/24
>> but this doesn't work as expected, and 100.100.100.0/24 route is only
>> being added to FIB-1 (second IP assignment command doesn't work, though it
>> returns no error).# setfib 1 netstat -rn ==> this fib has
>> 100.100.100.0/24 entry added in it# setfib 2 netstat -rn ==> nothing is
>> added here.
>>
>
> there are some sysctls that control some of this. have you investigated
> them?
>
> Though, as I say, you really want to structure your problem around using
> vimage.  Each vimage instance can have identical interfaces etc, becasue
> they are effectively separate machines.  You can route between them
> internally to the machine and at one stage you could have a process with
> sockets on each net but I"m not sure if you can still do that easily.
>
>
>
>
>> Is there any way I can do this in FreeBSD?
>> Thank you.
>> _____________________________________________
>>
>