System doesn't detect unplugged network cable and doesn't set interface up properly with DHCP

[John Baldwin]

[ Adding Brooks, IIRC, he imported the current dhclient ]

On Friday, July 13, 2012 5:48:30 am Peter Jeremy wrote:
> On 2012-Jul-12 13:41:39 -0700, Yuri <yuri at rawbw.com> wrote:
> >I have the simplest possible DHCP setup: ifconfig_re0="DHCP" in 
> >/etc/rc.conf.
> >
> >When the system boots, it gets connected fine.
> >
> >Now,  I disconnect my laptop and connect it to another network.
> >When cable is disconnected, IP address of this interface stays the same, 
> >old one is not removed.
> >When I plug it into another network, the same IP address stays. New IP 
> >doesn't get set. This is bad.
> >So I have to manually do 'ifconfig re0 down && remove <OLD-IP> && 
> >ifconfig re0 up'.
> 
> This is a bug in dhclient - see PR bin/166656, which includes a fix.

I think this is the correct answer.  Brooks, can you look at the PR and patch?  
If you are busy I can commit it if you give the ok.

-- 
John Baldwin