Subject: Re: dhclient and backgrounding
To: Steven M. Bellovin <smb@cs.columbia.edu>
From: Zafer Aydogan <zafer@aydogan.de>
List: tech-net
Date: 11/15/2006 17:32:42
2006/11/15, Steven M. Bellovin <smb@cs.columbia.edu>:
> On Wed, 15 Nov 2006 16:32:27 +0100, Manuel Bouyer <bouyer@antioche.eu.org>
> wrote:
>
> > On Wed, Nov 15, 2006 at 04:07:56PM +0100, Zafer Aydogan wrote:
> > > hello list,
> > >
> > > does dhclient do no backgrounding ?
> > > I mean, if I turn on my computer (dhclient=yes) and forget to turn on
> > > my switch, which is connected to my router, who has a dhcp server, I
> > > do not get a lease when I turn it back on afterwards.
> > >
> > > I thought, that dhclient would sit and wait until it notices the dhcp
> > > server is back up and then requests a lease so that I can get an IP
> > > Adresss, but nothing happens.
> > >
> > > The dhclient process is still alive and the only way I know to
> > > workaround this is to pkill dhclient and restart dhclient.
> > >
> > > Am I missing something ?
> >
> > >From what I remember dhclient finally gets an IP, but you have to wait several
> > minutes (10 to 15 maybe). But this was several releases ago ...
> >
> See the dhclient.conf man page -- you can change 'retry' (and some other
> timer-related options) to change that behavior.
>
>                 --Steven M. Bellovin, http://www.cs.columbia.edu/~smb
>
I did. It looks promising. But it didn't work.
I run tcpdump and kept an eye on it.
The man page says the default retry time is 5 minutes.
I waited 18 Minutes and nothing happened. The interface is up and
active but has still no IP.


and Hubert's quote doesn't work either.
"from dhclient(8): ``Old leases are kept around in case the DHCP server is
unavailable when dhclient is first invoked (generally during the initial
system boot process).  In that event, old leases from the dhclient.leases
file which have not yet expired are tested, and if they are determined to
be valid, they are used until either they expire or the DHCP server
becomes available.''

I see the message "using old lease 192.168.0.203", but the interface
doesn't get configured.


Anything else I can do ?
I'm running current from 8th Nov. and my ethernet interface is fxp0.
(It's running very well.)
Is this maybe a dhclient bug ?
Zafer.