ISC DHCP and DNS Integration

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>X-Original-To: dhcp-serverwebster.isc.org
>Date: Mon, 13 Feb 2006 19:55:34 -0600
>From: Carl Karsten <carlpersonnelware.com>
>To: dhcp-serverisc.org
>Subject: Re: ISC DHCP and DNS Integration
>X-ecartis-version: Ecartis v1.0.0
>X-original-sender: carlpersonnelware.com
>X-List-ID: <dhcp-server.isc.org>
>
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>/dev/rob0 wrote:
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>> 
>> On Sunday 2006-February-12 20:30, Carl Karsten
wrote:
>>> What defines what the name is?  As in,
WorkstationA boots, does a
>>> dhcp request, gets an IP and is on its way. 
Now I am on WorkstationB
>>> and want to ping A. what name do I use?
>> 
>> "option domain-name" defines both the
name of your zone and the search 
>> order used by resolver clients. You'd use the
hostname provided by the 
>> client and your domain name, which can be omitted
if your resolver is 
>> doing the search.
>
>So WorkstationA's hostname is BoxA and the DHCP server
gives it 1.2.3.4.  How 
>does the DNS server ever get "BoxA"
associated with 1.2.3.4?
>
>^C

Hi Carl,

Suggest you read the man page for dhcpd.conf, scroll down to
the
section DYNAMIC DNS UPDATES. Skip over the part about the
Ad-Hoc Method
and go down to the Interim Method, which is what everyone
uses. This
describes the steps the dhcp server goes through,
constructing the
client name, the DNS records that get updated, and so on.

There are also some Draft Standard docuemtns included in the
doc
directory in the dhcpd source distribution.

If you need more information on the DNS side, then the BIND
Admin
Reference Manual (ARM) would be a good place to start. It's
included
with the BIND distribution, but the installation directory
depends
on your operating system layout.

The short answer to your question above is that dhcpd sends
a dynamic
DNS update to the DNS server to tell it to add a an A record
and a PTR
record to the DNS zone file.

regards,
-glenn


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Ok, I think I get how the name is defiened: the client may
supply a string, the 
server may use it, and end the end, the dhcp server ends up
with a string which 
it sends to bind.

Read the man pages for dhcpd, dhcpd.conf, named and
named.conf.  I cut/pasted 
the examples into my .conf's, and still nothing.  DHCP is
still assigning IP's 
and DNS is still resoving names, but the 2 don't seem to be
aware of each other: 
nothing in either log files about the other.

I was able to use nsupdate to add a host, which also
produced things in the log 
file, including errors when I didn't do it right the first
few times.  This 
makes me think dhcp isn't trying.

rootshaz:~ # dhcpd3 -v
Internet Systems Consortium DHCP Server V3.0.1

I can't imagine this is a new feature.

Will the [-tf trace-output-file] have anything in there
about ddns?

Is there some way to increase how much gets logged?

^C

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Carl Karsten wrote:

>Ok, I think I get how the name is defiened: the client
may supply a 
>string, the  server may use it, and end the end, the
dhcp server 
>ends up with a string which it sends to bind.

Correct

>Read the man pages for dhcpd, dhcpd.conf, named and
named.conf.  I cut/pasted
>the examples into my .conf's, and still nothing.  DHCP
is still assigning IP's
>and DNS is still resoving names, but the 2 don't seem
to be aware of 
>each other:
>nothing in either log files about the other.

In that case, can you post your dhcpd.conf and named.conf
files, and 
the zone files for the forward and reverse zones you are
trying to 
update ?

>rootshaz:~ # dhcpd3 -v
>Internet Systems Consortium DHCP Server V3.0.1
>
>I can't imagine this is a new feature.

Correct, it isn't a new feature (it should be working with
3.0.1), 
but that version is now very old. Current version is
3.0.3<something>.

Simon

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Along these lines, is there a wiki where I can list some
tips for getting ddns 
working?

For instance, using dhcpcd -T -h SomeName to test dhcpd, and
nsupdate to test named.

Also, I just figured out that named actually modifies the
/etc/bind config files.

^C

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Carl Karsten wrote:

>Along these lines, is there a wiki where I can list some
tips for getting ddns
>working?

I don't think it covers this yet, you could consider
contributing to 
http://dhcp-monger.est-unique.net/wakka.php?wiki=Welcome



>Also, I just figured out that named actually modifies
the /etc/bind 
>config files.

Does it ? It's the first time I've heard of this. I think
you'll find 
that it only modifies the zone files for zones with update
capability.

Simon

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