Understanding the interplay of ipfw, vlan, and carp

[Freddie Cash]

On March 4, 2008 02:20 pm Max Laier wrote:
> Am Di, 4.03.2008, 22:51, schrieb Freddie Cash:
> ...
>
> > The lack of a "carpdev" option to directly link a carp device to an
> > interface (similar to "vlandev" for vlan(4)) is what's really
> > tripping me up.  It appears the carp(4) driver looks at all the
> > interfaces in the box to find one with an IP in the same subnet as
> > the carp IP and then uses that as the physical device.
>
> You could try the attached patch.  It adds carpdev support.  You'll
> have to recompile ifconfig to make use of it.
>
> This patch has some shortcomings that I wanted to address for a long
> time now, but never found the time to do so.  Mostly that IPv6 over
> CARP is broken with this patch.  Everything else is supposed to work
> and I'd like to hear if you experience otherwise (success stories
> welcome, too).  This is from back in early January, but should apply to
> RELENG_7 and HEAD w/o too much trouble.
>
> Any feedback appreciated!

I'm in the process of upgrading a test box to RELENG_7_0.  I'll see if I 
can get this patch to apply to that.  The lack of IPv6 support won't 
affect us.

Just to make sure I understand how it'll work:
  - bring up the physical device (ifconfig em1 up)
  - create the vlan device (ifconfig vlan100 create; ifconfig vlan100 ...)
  - create the carp device (ifconfig carp2 carpdev vlan100 ...)

The physical device and the vlan device won't need IPs, just the carp 
device?  Or will I still need to configure an IP/subnet on the vlan 
interface?

Thanks for this, I'll let you know how it works out.
-- 
Freddie Cash
fjwcash at gmail.com