svn commit: r193199 - head/etc

John Baldwin jhb at
Tue Jun 2 19:11:10 UTC 2009

On Tuesday 02 June 2009 12:50:21 pm Brooks Davis wrote:
> On Tue, Jun 02, 2009 at 04:45:31PM +0100, Bruce Simpson wrote:
> > Brooks Davis wrote:
> >> ...
> >>> On boot time I instantiate a tap0 instance from cloned_interfaces=".." 
> >>> /etc/rc.conf, and then use ifconfig_tap0="..." to clone the MAC address 
> >>> on the tap instance from the internal Ethernet port, as there is no 
> >>> way of uniquely identifying the client for an automated bootstrap.
> >>> 
> >>> This happens from within a flash image.
> >>>     
> >> 
> >> I see nothing related to network_interfaces here...
> >>   
> > 
> > I did explicitly name them there, so there would be no automated DHCP 
> > of any interfaces, even if hot-plugged. Perhaps I am thinking of 
> > cloned_interfaces=""...
> cloned_interfaces is different and will definiterly remain since you've
> got to create them some how.  They get created early and thus end up on
> the list.  Also, there's no need to worry about hot plugged interfaces
> getting margically configured to do dhcp.  For the system to do
> something with an interface they following must be true:
>  - It makes it in to the list of interfaces some how
>  - It actually exists or is create early in the process via
>    cloned_interfaces, gif_interfaces, etc
>  - The ifconfig_<if> variable is set (I think i can be "", but "up" is
>    alwasy a good choice if you just want a stub.
>  - The ifconfig_<if> variable must not contain the NOAUTO keyword.
> If all of those things are true, the interface will be configured at
> startup or on insert.  Otherwise, it won't be.

I think more specifically, if you don't set 'ifconfig_<if>' to "DHCP", then 
when you plug a <if> device in, nothing happens.  DHCP is opt-in, not 
opt-out.  The only reason one would want to limit network_interfaces is if 
you wanted to have an ifconfig_foo0 line in /etc/rc.conf but not have foo0 
configured automatically.  But you can already accomplish that via either 
the 'NOAUTO' keyword or just not having a bogus ifconfig_foo0 line.  Given 
that, there really isn't a good reason to customize network_interfaces 

Unless someone has a real usage case that NOAUTO, etc. doesn't cover, I think 
this commit should be reverted.

John Baldwin

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