>Date: Mon, 5 Mar 2007 18:01:02 +0100
>From: Jeremie Le Hen <jeremie le-hen.org>
>To: dhcp-usersisc.org
>
>Hi list,
>
>On Sun, Mar 04, 2007 at 08:49:40PM +0100, Jeremie Le Hen
wrote:
>> I have been looking for PXE HOWTOs and I saw
numerous options that
>> seems to overlap themselves. I've read what I
could in dhcpd.conf(5)
>> manpage and glanced at RFC1533 as well but I'm
still bewildered.
>>
>> Some setups use "server-name", some
others "next-server". I even
>> saw "option tftp-server-name" sometimes.
Most of the time they
>> all have the same value.
>>
>> I think that "server-name" is just a
string identifying the DHCP
>> server, though I don't really understand the
purpose of such an option.
>> The "next-server" option seems to
describe the IP address (or
>> FQDN) or the TFTP server.
>>
>> Am I right ? In this case, what's the usefulness
of
>> "option tftp-server-name" ?
>>
>> I would be glad of someone could point out the
reference or a
>> description for this.
>
>I think I succeeded to gather enough informations about
this to
>reply myself, for the record.
>
>* "server-name" is just an informative name,
giving the real name
> of the DHCP server.
man dhcpd.conf
server-name name ;
The server-name statement can be used to inform the
client
of the name of the server from which it is booting.
Name
should be the name that will be provided to the
client.
My reading is that this is the name of the dhcp server.
>* "next-server" is the ``address of the server
to use in the next step
> of the client's bootstrap process''. No protocol is
specified and
> hence I assume this is implementation-defined.
man dhcpd.conf
next-server server-name;
The next-server statement is used to specify the
host
address of the server from which the initial boot
file
(specified in the filename statement) is to be
loaded.
Server-name should be a numeric IP address or a
domain
name.
The protocol could be tftp, or ftp or nfs or something else.
It is
something that is configured on the appropriate server
knowing the
behaviur of the client. Often, however, it does use tftp.
Whatever
follows once the initial boot file has been downloaded is up
to the
client. It is asumed that the client either knows what to do
next, or
that information is in the bootfile.
>* "tfp-server-name" is just an informative
name as well, when the
> "sname" (server-name) field has been used
for DHCP options.
man dhcp-options
option tftp-server-name text;
This option is used to identify a TFTP server and, if
sup-
ported by the client, should have the same effect
as the
server-name declaration. BOOTP clients are
unlikely to
support this option. Some DHCP clients will
support it,
and others actually require it.
This is carried as a different dhcp option number, so it is
different
to next-server. It is specific to tftp. Not all clients can
use this
option.
For a full description of these concepts you could refer to
RFC2131 -
this is the dhcp RFC. However, the names are specific to ISC
dhcp
server.
HTH.
regards,
-glenn
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