Re: DHCP client ID in svn3846

[Dan Williams <dcbw redhat com>]

On Wed, 2008-08-13 at 08:54 -0400, Neal Becker wrote:
> On Wednesday 13 August 2008, Dan Williams wrote:
> > On Wed, 2008-08-13 at 08:46 -0400, Neal Becker wrote:
> > > I'm testing NetworkManager-0.7.0-0.11.svn3846.fc9.x86_64.
> > >
> > > I'm guessing that the option
> > > DHCP client ID
> > > in editing auto ethernet/IPv4 Settings should set DHCP_HOSTNAME?  It
> > > doesn't (as shown in /var/run/nm-dhclient-eth0.conf)
> > >
> > > Also, I _do_ have DHCP_HOSTNAME set in
> > > /etc/sysconfig/network-scripts/ifcfg-eth0, but this seems to be ignored.
> >
> > Unfortunately dhcp client id and dhcp hostname are actually two
> > different things.  I'll check about the DHCP_HOSTNAME thing; if that's
> > not working it's a bug.
> >
> > Dan
> 
> If they are 2 different things, then what is the preferred method to set 
> DHCP_HOSTNAME?  Seems reasonable to add it to the NM edit gui.

Is what you put in DHCP_HOSTNAME the same as your local hostname?  If
not, why?

There's a limit to what stuff can be put into the UI, and I don't think
having an entry for an option that we can likely probably scrape from
gethostname(2) gets over the bar.  The client ID is quite a bit more
often used from what I can tell, because in many setups it's actually
_required_ to get get real connectivity.  The hostname thing is more of
a convenience option to let you refer to your machine by a known name.

> BTW, what is DHCP client ID then?

An arbitrary identifier sent to the DHCP server to reserve a specific IP
address for your machine, usually the MAC address or some other unique
ID.

The "dhcp hostname" option just sends a hostname to the DHCP server,
which (if configured correctly) forwards that hostname on along with
your IP address to a DNS server.

Dan