Jeevan Mathew
03/05/2008 1:21 PM
post5543
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Hi,
Perhaps this are getting started questions, but however:
Assume a default installation whith mode dhcp in /etc/net.cfg .
Who starts dhcp.client ?
When and where (sysinit ?) ?
and the docs say:
-h hostname
Hostname of client (default is supplied by the server if the hostname is available).
Is that the hostname reported by the hostname utility ?
And are there possible dhcp-servers which doesn't provide hostnames ?
THX,
Jeevan
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Robert Craig
03/05/2008 1:41 PM
post5547
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dhcp.client is started by netmanager (who parses the net.cfg file).
netmanager is started by the enumerators (see /etc/system/enum/devices/net)
The -h option to dhcp.client will override whatever the dhcp server provides
(if anything; the server doesn't have to provide a name).
Now comes the confusing bit... The hostname dhcp.client configures doesn't
appear to be reflected by the hostname utility.
Robert.
-----Original Message-----
From: Jeevan Mathew [mailto:jmathew@t-online.de]
Sent: Wednesday, March 05, 2008 1:21 PM
To: general-networking
Subject: dhcp.client qs:
Hi,
Perhaps this are getting started questions, but however:
Assume a default installation whith mode dhcp in /etc/net.cfg .
Who starts dhcp.client ?
When and where (sysinit ?) ?
and the docs say:
-h hostname
Hostname of client (default is supplied by the server if the hostname is
available).
Is that the hostname reported by the hostname utility ?
And are there possible dhcp-servers which doesn't provide hostnames ?
THX,
Jeevan
_______________________________________________
General
http://community.qnx.com/sf/go/post5543
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Jeevan Mathew
03/05/2008 2:19 PM
post5553
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> dhcp.client is started by netmanager (who parses the net.cfg file).
> netmanager is started by the enumerators (see /etc/system/enum/devices/net)
Damned, You got me Robert :-).
Sorry, I forgot why I have forgotten this.
>
> The -h option to dhcp.client will override whatever the dhcp server >provides (if anything; the server doesn't have to
provide a name).
'override' sounds good. So if the server doesn't provide a name the empty space in some dhcp-server's table is overriden
with whatever name is specified with the -h option .
Can you confrim this ?
>
> Now comes the confusing bit... The hostname dhcp.client configures doesn't
> appear to be reflected by the hostname utility.
>
I can live with this , if the above override takes effect even if the dhcp-server doesn't provide the name. (The case
set that the server allows some new table entry.)
Regards,
Jeevan
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Robert Craig
03/05/2008 3:03 PM
post5557
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The mysteries of booting are easily forgotten... :->>
With regards to the hostname,
The -h modifies the name that the client knows itself by.
The server question that you're asking is two fold.
Firstly, does our client return the new hostname to the server (I'd have to
check, or maybe someone else will jump in and answer).
Secondly, will the server update the DNS name data base if it is sent the
information by the client. For this, the server has to be running a Dynamic
DNS server which allows the DHCP server to update the DNS database with
client information. I suspect that our named might be of a vintage where
this isn't supported but, again, I'd have to verify.
What type of system is the server?
Robert.
-----Original Message-----
From: Jeevan Mathew [mailto:jmathew@t-online.de]
Sent: Wednesday, March 05, 2008 2:19 PM
To: general-networking
Subject: Re: RE: dhcp.client qs:
> dhcp.client is started by netmanager (who parses the net.cfg file).
> netmanager is started by the enumerators (see
/etc/system/enum/devices/net)
Damned, You got me Robert :-).
Sorry, I forgot why I have forgotten this.
>
> The -h option to dhcp.client will override whatever the dhcp server
>provides (if anything; the server doesn't have to provide a name).
'override' sounds good. So if the server doesn't provide a name the empty
space in some dhcp-server's table is overriden with whatever name is
specified with the -h option .
Can you confrim this ?
>
> Now comes the confusing bit... The hostname dhcp.client configures
doesn't
> appear to be reflected by the hostname utility.
>
I can live with this , if the above override takes effect even if the
dhcp-server doesn't provide the name. (The case set that the server allows
some new table entry.)
Regards,
Jeevan
_______________________________________________
General
http://community.qnx.com/sf/go/post5553
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Dave Brown
03/06/2008 3:52 AM
post5572
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The dhcp.client -h option provides two services, one is to override the
hostname that may be supplied by the server, and the other is to pass the
hostname to the server. This information might be a bit dated as I have not
check host behavior recently, but what the -h option does is mimic a Windows
DHCP client implementation. When invoking DHCP Windows would include its
current hostname in the DHCP request and its hostname could not be
overridden. What the DHCP server does with this information depends on the
server configuration. A Windows DHCP server may use this information to
update the nameserver while another implementation may not (for example you
overrode locally the hostname it intended to assign). The main reason it was
added is that cable internet service providers at the time were using the
hostname as a form of authentication. Your home system ( Only Windows would
be supported of course ;) ) was assigned a 'Computer Name', and when it
booted, it would send this name (hostname) as part of the DHCP request. If
the hostname was not present, the DHCP server would not respond. I have not
had a cable ISP for some time, but I don't think they require this any
longer.
Dave
> -----Original Message-----
> From: Robert Craig
> Sent: Wednesday, March 05, 2008 3:03 PM
> To: general-networking
> Subject: RE: RE: dhcp.client qs:
>
> The mysteries of booting are easily forgotten... :->>
>
> With regards to the hostname,
>
> The -h modifies the name that the client knows itself by.
>
> The server question that you're asking is two fold.
>
> Firstly, does our client return the new hostname to the server (I'd have
> to
> check, or maybe someone else will jump in and answer).
>
> Secondly, will the server update the DNS name data base if it is sent the
> information by the client. For this, the server has to be running a
> Dynamic
> DNS server which allows the DHCP server to update the DNS database with
> client information. I suspect that our named might be of a vintage where
> this isn't supported but, again, I'd have to verify.
>
> What type of system is the server?
>
>
> Robert.
>
>
> -----Original Message-----
> From: Jeevan Mathew [mailto:jmathew@t-online.de]
> Sent: Wednesday, March 05, 2008 2:19 PM
> To: general-networking
> Subject: Re: RE: dhcp.client qs:
>
> > dhcp.client is started by netmanager (who parses the net.cfg file).
> > netmanager is started by the enumerators (see
> /etc/system/enum/devices/net)
>
> Damned, You got me Robert :-).
> Sorry, I forgot why I have forgotten this.
>
> >
> > The -h option to dhcp.client will override whatever the dhcp server
> >provides (if anything; the server doesn't have to provide a name).
>
> 'override' sounds good. So if the server doesn't provide a name the empty
> space in some dhcp-server's table is overriden with whatever name is
> specified with the -h option .
> Can you confrim this ?
>
> >
> > Now comes the confusing bit... The hostname dhcp.client configures
> doesn't
> > appear to be reflected by the hostname utility.
> >
>
> I can live with this , if the above override takes effect even if the
> dhcp-server doesn't provide the name. (The case set that the server allows
> some new table entry.)
>
> Regards,
> Jeevan
>
>
>
>
>
> _______________________________________________
> General
> http://community.qnx.com/sf/go/post5553
>
> _______________________________________________
> General
> http://community.qnx.com/sf/go/post5557
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Jeevan Mathew(deleted)
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Re: RE: RE: dhcp.client qs:
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Jeevan Mathew(deleted)
03/06/2008 6:59 AM
post5573
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Re: RE: RE: dhcp.client qs:
Thanks Robert and Dave,
>The dhcp.client -h option provides two services, one is to override the
>hostname that may be supplied by the server, and the other is to >pass the hostname to the server. This information
might be a bit >dated as I have not check host behavior recently, but what the -h >option does is mimic a Windows DHCP
client implementation. When >invoking DHCP Windows would include its current hostname in the >DHCP request and its
hostname could not be overridden. What the >DHCP server does with this information depends on the server >configuration.
A Windows DHCP server may use this information to
>update the nameserver while another implementation may not (for >example you overrode locally the hostname it intended
to assign). The >main reason it was added is that cable internet service providers at the >time were using the hostname
as a form of authentication. Your >home system ( Only Windows would be supported of course ;) ) was >assigned a
'Computer Name', and when it booted, it would send this >name (hostname) as part of the DHCP request. If the hostname
was >not present, the DHCP server would not respond. I have not had a >cable ISP for some time, but I don't think they
require this any longer.
>
> Dave
Fantastic infos. Things are fine now.
(The server in question is a Novell DHCP V3)
Swiching the server into debug mode and starting "dhcp.client -h somename" showed that the name is indeed submitted .
At least mac and string reached the server.
(core_networking] / trunk / services / dhcp.client / dhclient.c )
...
for(count=1;count<=8;count=count*2){
result = send_packet (interface, (struct packet *)0,
&raw, outgoing.packet_length,
raw.siaddr, &to, (struct hardware *)0);
... ?
However:
From a QNX standard user/Admin_of_SomeCompany point of view reading the docs it is difficult to....
(http://www.qnx.com/developers/docs/6.3.0SP3/neutrino/utilities/p/phlip.html ) :
[]
ID
Normally, you don't need to fill in this field. Typically, a DHCP server allocates an identity for a client and sends
that identity to the client automatically; the identity then becomes the client machine's hostname. Sometimes, an ISP
will provide an identity separately and a client is expected to enter this identity as a security measure when they log
in. If you are told to use such an ID, enter it here, otherwise leave the field blank.
[]
....guess where to set the ID, as the next picture of phlip' s Devices Tab shows the Manual mode and not the dhcp mode.
So for the mininum I would appreciate a hint to the -h option of dhcp.client from within the doc-text block snipplet
above.
I will file a doc PR as this seem to be a FAQ:
see:
http://community.qnx.com/sf/go/topc1548
Thanks again for all Your expertise on this.
Jeevan
>
>
> > -----Original Message-----
> > From: Robert Craig
> > Sent: Wednesday, March 05, 2008 3:03 PM
> > To: general-networking
> > Subject: RE: RE: dhcp.client qs:
> >
> > The mysteries of booting are easily forgotten... :->>
> >
> > With regards to the hostname,
> >
> > The -h modifies the name that the client knows itself by.
> >
> > The server question that you're asking is two fold.
> >
> > Firstly, does our client return the new hostname to the server (I'd have
> > to
> > check, or maybe someone else will jump in and answer).
> >
> > Secondly, will the server update the DNS name data base if it is sent the
> > information by the client. For this, the server has to be running a
> > Dynamic
> > DNS server which allows the DHCP server to update the DNS database with
> > client information. I suspect that our named might be of a vintage where
> > this isn't supported but, again,...
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