freebsd stable - Oct 2010 - How dhcp client can set its hostname properly on lease time

Hi,

I'm using FreeBSD 8 stable as of 20101006. It is a dhcp client in a
private local network, and xorg staff is installed. When I tried to use
it from a remote pc with X11-forwarding set, xauth failed to set up
.Xauthority as follows.

/usr/local/bin/xauth: creating new authority file /home/hogehoge/.Xauthority
/usr/local/bin/xauth: (stdin):1: bad display name "unix:10.0" in
"remove" command
/usr/local/bin/xauth: (stdin):2: bad display name "unix:10.0" in
"add"
command

At this moment, hostname was not set (it's empty) because the FreeBSD
box was a dhcp client. Meanwhile, if the hostname coresponding to the
ip-address assigned by dhcp server was set manually, the above lines
disappeared and X11-forwarding worked well.


Now, my question is

Are there good way for dhcp client to set its hostname properly on lease
time?


The following will be a possble workaround, but I'm wondering there can
be a smart answer in FreeBSD itself.

It is possible to resolve the hostname corresponding to a dhcp-delivered
ip-address with a local name server. So, (1) resolve the corresponding
hostname from the local name server, (2) set it as hostname, and (3)
call them every time when dhcp lease is updated


Cheers

--
-----
Mamoru IWAKI
Grad. Schl. Sci & Tech./Dept. Biocybernetics, Niigata University

Regarding your posting to freebsd-stable.

Probably what you want to do is have the DHCP server send the machine name
when it offers a lease to the client.

-Kurt

On Thu, Oct 07, 2010 at 09:37:52PM +0900, Mamoru Iwaki
wrote:
> Now, my question is
> 
> Are there good way for dhcp client to set its hostname properly on lease
> time?
Depends on 'properly'.

I've hacked dhclient exit scripts to synthesize a hostname, if one
was not offered by the DHCP server.  The host, under these
circumstances, gets a hostname derived from the IP address and the
supplied domain name, eg: '10-12-34-56.example.com'.

This at least gets the box into a place where it has a hostname
associated with the address on an external interface.

No one else knows that hostname, however.  YMMV.
> 
> Cheers
> 
> --
> -----
> Mamoru IWAKI
> Grad. Schl. Sci & Tech./Dept. Biocybernetics, Niigata University
-- 
Brian Reichert				<reichert@numachi.com>
55 Crystal Ave. #286			
Derry NH 03038-1725 USA			BSD admin/developer at large

On Thu, 07 Oct 2010 21:37:52 +0900
Mamoru Iwaki <1wkmmr@gmail.com> wrote:
> Are there good way for dhcp client to set its hostname properly on lease
> time?
Well, you *can* have the dhcp client on FreeBSD send an identifier, and
with that identifier the dhcp server can assign the client a static ip
lease. If that static ip is registered in your local dns, you're all
set. Doesn't work well if you use the client on another network who
doesn't offer static ip's. YMMV.
> The following will be a possble workaround, but I'm wondering there can
> be a smart answer in FreeBSD itself.
> 
> It is possible to resolve the hostname corresponding to a dhcp-delivered
> ip-address with a local name server. So, (1) resolve the corresponding
> hostname from the local name server, (2) set it as hostname, and (3)
> call them every time when dhcp lease is updated
Isn't the proper way with dns to configure dynamic DNS updates, and
allow the client to do that?

HTH
-- 
Regards,
Torfinn Ingolfsen

Hi,

Thanks everyone for giving me useful reply.
Now, my stupid problem has been solved by setting 'get-lease-hostnames 
true;' in dhcpd.conf file.

Cheers

(4:59), Mamoru Iwaki wrote:
>   Hi,
>
> I'm using FreeBSD 8 stable as of 20101006. It is a dhcp client in a
> private local network, and xorg staff is installed. When I tried to use
> it from a remote pc with X11-forwarding set, xauth failed to set up
> .Xauthority as follows.
>
> /usr/local/bin/xauth: creating new authority file
/home/hogehoge/.Xauthority
> /usr/local/bin/xauth: (stdin):1: bad display name "unix:10.0" in
> "remove" command
> /usr/local/bin/xauth: (stdin):2: bad display name "unix:10.0" in
"add"
> command
>
> At this moment, hostname was not set (it's empty) because the FreeBSD
> box was a dhcp client. Meanwhile, if the hostname coresponding to the
> ip-address assigned by dhcp server was set manually, the above lines
> disappeared and X11-forwarding worked well.
>
>
> Now, my question is
>
> Are there good way for dhcp client to set its hostname properly on lease
> time?
>
>
> The following will be a possble workaround, but I'm wondering there can
> be a smart answer in FreeBSD itself.
>
> It is possible to resolve the hostname corresponding to a dhcp-delivered
> ip-address with a local name server. So, (1) resolve the corresponding
> hostname from the local name server, (2) set it as hostname, and (3)
> call them every time when dhcp lease is updated
-- 
-----
Mamoru IWAKI
Grad. Schl. Sci & Tech./Dept. Biocybernetics, Niigata University