how to add flags to ifconfig at boot

David Kelly dkelly at
Thu Sep 21 09:38:30 PDT 2006

On Thu, Sep 21, 2006 at 07:24:21AM -0700, Bill Schoolcraft wrote:
> --- David Kelly <dkelly at> wrote:
> > True only if your options for ifconfig in rc.conf would clear or
> > override whatever it is you put in /etc/start_if_em0. As long as its
> > something that can be done with multiple ifconfigs then all is fine.
> > 
> > For example this works fine in /etc/start_if.xl0:
> > 
> > #!/bin/sh
> > ifconfig xl0 lladdr 00:01:23:45:67:89
> > 
> > with this in rc.conf:
> > ifconfig_xl0="DHCP"
> Thank you very much for the above info David, I've always been
> challenged with my (encrypted) wireless card though, and usually have
> my own manual script that I run.  Always wanted to have it start
> "automagically" when/if it is the card I'm using.
> (question)
> Besides the single line you have in /etc/rc.conf above to instruct DHCP
> to be used, can one place all the following somehow in rc.conf or will
> I have to get this going in a script location?
> Currently I give my card a static ip but would like to have it grab
> it's ipaddr by DHCP, here is the majority of the script, omitted are
> my ping tests of the gateway at the end.

The reason you do not put a script such as you describe within rc.conf
is that rc.conf is widely sourced as part of other scripts. As such, its
run many times, not just once at boot.

I think you should be able to remove the ifconfig setting static IP
address, and the "route add" from your script, name the script
if_start.wi0, and add "ifconfig_wi0='DHCP'" to rc.conf and be in
business (assuming your wireless access point serves DHCP).

Thats the whole point of start_if.<if_name>, to do things such as change
MAC addresses, set WEP keys, etc. Things which lack formal support in

David Kelly N4HHE, dkelly at
Whom computers would destroy, they must first drive mad.

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