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Re: LDAP and DNS



Well if you follow any of the interviews with Tim Howes (aka the Father of
LDAP), you'll realize that LDAP is not designed to replace DNS. DNS is a
very specific directory application that requires special optimizations.
LDAP of course can help store some DNS information (e.g. the InterNIC WhoIs
database would be a perfect example), but using LDAP for traditional DNS
lookups probably isn't pratical in the long-run. While I think LDAP security
and replication are top-notch, it's write performance stinks. DNS changes
alot, so that's something to really consider.

DNS does need to be reworked (but the fact that it has scaled as well as it
has says a lot), but I think it's going to require a very similar solution
that will need to be highly optimized for this environment.

on the other hand, it probably does make sense for LDAP to store some
information including IP/hostname information about an object. This will
probably become more apparent when JINI network devices start to appear.
E.g. a device connects to the network, finds an LDAP server (probably
through the service location protocol), then registers itself with the LDAP
server, e.g. I'm a toaster, here's my current specs (I can handle two slices
of bread, I'm electric, my current setting is golden-brown, etc). Then the
JINI server can issue an IP address (and perhaps a hostname) to the toaster,
perhaps placing it in the LDAP server so that the toaster doesn't have to
query DNS or something similar to find it's hostname each time it wants to
communicate.

later,

Mark




-----Original Message-----
From: Jeff Clowser <jclowser@aerotek.com>
To: Jon Sellers <jsellers@manatee.brev.lib.fl.us>
Cc: openldap-general@OpenLDAP.org <openldap-general@OpenLDAP.org>
Date: Tuesday, June 22, 1999 5:07 PM
Subject: Re: LDAP and DNS


>I would think that a nice compromise in a product would be something
>like the following:
>
>DNS entries are maintained in LDAP - you could keep ip and hostname
>info in a record, and expand it to include all kinds of other info
>for record keeping (i.e. person responsible for the machine, machine
>type, location, etc).
>
>Have a "primary" DNS server that backends to LDAP - this would have to
>be a custom hack to something like bind.
>
>Have 2 or more secondaries that do their zone transfers from this
>"primary" server.  These could be unmodified versions of bind.
>
>Register only these secondary DNS servers for users, Internic, etc.
>i.e. the _only_ purpose of the "primary" server would be to read
>LDAP and do zone transfers to your other DNS servers, so you manage
>it in LDAP, but for performance, you use standard tuned bind DNS servers.
>
>As a side note, I would make the ip/dns record just have ip/hostname info
>in it, have a separate record for the machine (for inventory purposes,
>recording what it is, SN, inv. #, etc), and a separate record for the
>user responsible.  The IP/hostname record would hold the DN of the
>machine it is used on, and the machine record would hold the
>dn of the responsible person (maybe even the location would be a dn
>to an office/location record) - building these relations can avoid
>duplicate/bad data, though it will require more lookups to gather all
>the data related to the ip (i.e. 4 lookups to find the ip, machine,
>user responsible, and location of the machine).  The DNS server
>is only worried about the ip to name mapping, so only needs the first
>record.  These additional lookups only happen when managing a dns address.
>Allows you to create a nice user management console where deleting a user
>automagically tells you what equiment they have signed out so you can
>collect it.  If it's a server tied to a users record that also has
>email info, you can do things like monitor the a server and know who
>to email via a script if it goes down by finding the IP # and tracing
>it to the machine, then the user(s).
>Nice managed enterprise :)
>
>Long way to get to my final point, which is that I don't know of
>any software that actually does this...  Just some ideas in case someone
>wants to build it - this would take care of the performance question,
though.
>
>Jon Sellers wrote:
>
>> Don't know. That is the kind of thing I was hoping to find out with my
original
>> message. I would expect that there isn't right now, but if LDAP becomes
as
>> ubiquitous as DNS won't it need to come close?
>>
>> Another question might be "Is there an LDAP server that can handle the
number
>> of queries per second that my DNS handles?
>>
>> Jon
>>
>> >On Tue, 22 Jun 1999, you wrote:
>> > Jon,
>> >
>> > Is there an LDAP server that can handle the number of queries
>> > per second that DNS can handle?
>> >
>> > --Pete
>> >
>> > Jon Sellers wrote:
>> > >
>> > > Has anyone done any work on integrating OpenLDAP and DNS? I suppose
the right
>> > > way to approach it would be to patch bind to query an LDAP server
instead of
>> > > it's standard configuration files (though I know zip about bind's
internals).
>> > > Or maybe someone knows of a DNS implementation that already does
this?
>> > >
>> > > Jon
>> >
>> > --
>> > ====================================================================
>> > Peter E. Stoddard, Consultant         Pete.Stoddard@compaq.com
>> > ISP Solutions Business Unit           Tel. (603) 884-5128
>> > Compaq Computer Corporation           Fax. (603) 884-0627
>> > 110 Spit Brook Road, ZKO2-2/N87
>> > Nashua, New Hampshire 03062-2698
>> > USA
>> > ====================================================================
>
>--
> Jeff Clowser
> mailto:jclowser@aerotek.com       Hanover MD  21076 USA
> Phone: (410)-579-4328             7312 Parkway Drive
>
>
>
>
>