
----------------------------------------------------------
NOV-DHC2.DOC -- 19980327 -- Email thread on NetWare & DHCP
----------------------------------------------------------

	Feel free to add or edit this document and then email
	it back to faq@jelyon.com




Date: Mon, 19 Jan 1998 14:09:30 +0000
From: Phil Randal <philr@HWCCES.DEMON.CO.UK>
Subject: Re: DHCP on NetWare 3.12

>Does anyone know of a product that performs the same features as DHCP
>but runs on [NW] 3.12?  I'm told DHCP doesn't run on 3.12 but Novell
>does have a product for that version which is very similar and runs
>great.  Anyone know what its called or where I can obtain a copy?

	ftp://ftp.novell.com/pub/netwire/nsd/dhcp21o.exe

------------------------------

Date: Mon, 19 Jan 1998 14:30:01 -0600
From: George Taylor <GTAYLOR@LHSNET.COM>
Subject: What parts of IP to install? -Reply

I can't say about DNS, but I know that DHCP does not need NWIP.

I run it on about 9 of our servers and all I do is:

 - Install TCPIP as you normally would
 - Run DHCPCFG to do the configuration you want
 - And then run DHCPSRVR

------------------------------

Date: Mon, 26 Jan 1998 10:32:02 +0000
From: Richard Letts <r.j.letts@SALFORD.AC.UK>
Subject: Re: How to change DHCP addresses

>Lease time for DHCP is 275 days, now the question is, what happens if I
>change the DHCP server to only hand out the new addresses?

Devices which have leased the old address will continue to use them

>Do I have to do a Refresh manualy on each workstation? shoul I delete
>the old handed out addresses from the DHCP server?

You have to manually release the address on each workstation

I suggest most people set lease times to 7 days: the load on the DHCP
servers is really quite minimal. we run one here which also does bootp for
over 5000 devices and the load is tiny in comparison to the DNS server
running on the same machine. Our lease time is 1 day.

The lease time should be set with the thought in mind "If I set it to X
days, then that is the time I have to wait before chnages take effect"

---------

Date: Mon, 26 Jan 1998 15:50:06 +0000
From: Richard Letts <r.j.letts@SALFORD.AC.UK>
Subject: Re: DHCP Server

>We're in the process of relocating the majority of our office workers.
>We originally hardcoded IP addresses on each workstation.  Faced with
>re-assigning IP addresses, it might be time to look at a DHCP server.
>Any info, experiences, warnings about the Netware DHCP server?

General DHCP warnings:
 - do not set the lease to less than 3 days; windows 95 has problems with
   this.
 - do not set the lease to longer than you can wait for 'planned' chnages.
I.e. if you set the lease to a year you'll either have to wait a year for
any chnages to take effect, or visit each machine personally to chekc it's
got the new information

I'd suggest a week as a good compromise

------------------------------

Date: Tue, 27 Jan 1998 09:46:51 +0000
From: Phil Randal <philr@HWCCES.DEMON.CO.UK>
Subject: Re: DHCP Server

>>general DHCP warnings:
>> - do not set the lease to less than 3 days; windows 95 has problems with
>>   this.
>
>What sort of problems? I've just reset the lease time from 'infinite' to
>2 hours on my DHCP server and haven't had any problems so far, but now
>you've got me worried...

There were very real problems with Novell's dhcp and Microsoft's
TCP/IP stack (search Novell's knowledgebase for DHCP) and you'll find
their explanation.  Microsoft's clients have a habit of hanging onto
their assigned address after the lease should have expired.

Here, with the default lease of 3 days, people who were on leave for
a week would come back to work and find an IP address conflict, with
Microsoft's IP stack stubbornly refusing to let go of the IP address.

We got round it by having long leases...  But when re restructured
our network, we had to reassign all IP addresses.

In win95, run winipcfg to obtain a new IP address.

In DOS/Win Client32, delete all c:\novell\client32\dhcpxxx.* files,
unload tcpip, then load tcpip and the address will be reassigned.

If I remember correctly, Novell claims that the latest
DHCP (ftp://ftp.novell.com/pub/netwire/nsd/dhcp21o.exe) solves the
problems with MS clients.

---------

Date: Tue, 27 Jan 1998 09:38:44 +0000
From: Phil Randal <philr@HWCCES.DEMON.CO.UK>
Subject: Re: DHCP Server

>DHCP2I.EXE (the file that you must download) is very simple to
>install, to manage, and to setup. The DhcpCfg.Nlm is a simple utility.
>If you'll use Dhcp in NetWare 3.x servers, you must hav the NetDb.Nlm
>file that does not come with Dhcp2I.Exe...

Try ftp://ftp.novell.com/pub/netwire/nsd/dhcp21o.exe (a hidden file).

It contains netdb.nlm, but may not install it under NW3.12.  Just
copy it to sys:system if that's the case.

------------------------------

Date: Tue, 27 Jan 1998 12:16:38 -0700
From: Joe Doupnik <JRD@CC.USU.EDU>
Subject: Re: More than 1 Novell-DHCP server??

>>Why would you want to??  DHCP is an extremely low utilization NLM as
>>far as the server is concerned and generates very little network traffic.  >>You're not going to gain anything having more than one DHCP server on
>>a single segment.
>
>If you have 5000+ devices obtaining their IP addresses from one server
>and it crashes...
>
>There's no protocol problem with having more than one DHCP server, as long
>as they are not both giving out the same dynamic address space. There is
>work in the DHCP working group about server<>server synronisation
>protocols. There are two proposals on the table: a loosely consistant
>approach which I can see will possibly lead to duplicate address
>assignment, and atightly syncronised version which won't.
>The latter currently appears to have found favour.
>
>If you read last year's brainshare slide they NDS/DHCP/DNS work appears
>to be very interesting. I'd like to see a released product though
>
>Richard Letts
---------
	Adding a small amount of technical info here.
	DHCP is designed like this. A client needing service broadcasts for
servers. Servers send an initial offer to the client. The client is supposed
to pick one response and send a broadcast (physical) reply to the selected
server saying Let's Do Business. The target server replies with a formal
written offer and the client accepts.
	The interesting step is in the middle where the broadcast reply is
sent, designed as a broadcast so all other servers can hear the client
pick one server. In the packets are the offered IP address, so in principle
the other servers could mark that IP address as being in-use. Alas that part
of the protocol fails to work because the latter stages of offer/acceptance
are point to point rather than broadcast and thus the other servers are never
sure the IP address has been allocated etc. This is just plain dumb, but what
else does one expect of committees and convoluted specs.
	There is a humorous replay of all this. The proposed revisions to
allocation of domain names (IP names) permit multiple registrars overlapping
the same name space. Guess how well these guys would synchronize to prevent
duplicate allocations. It's humorous to those with names, not so to those
acquiring them.
	Joe D.

------------------------------

From: "Tim Madden" <tmadden@aspenres.com>
Date: Mon, 2 Feb 1998 17:25:49 -0700
Subject: FAQ info on Win95 DHCP

Okay, here's how it is.  Win95 saves up to 8 previous DHCP IP
configurations in the registry key:

HKLM-System-CCS-Services-VxD-DHCP-DHCPInfoxx (where xx is 00-07).

By deleting these entries, you can force Win95 to ask for a new IP
address, and not insist on a previous one.  It's not quite that
simple, though.

Winipcfg will report the IP address, conflict or not, even after the
registry entry has been deleted.  This implies that the TCP/IP stack
has that address in memory.  If you don't release the address prior to
shutdown, the shutdown procedure will re-write the address to the
registry in the above key.  So, you need to delete the registry key
*and* release the address via winipcfg before shutting down.

Now, to the server side.  An NT DHCP server maintains the MAC-to-IP
address correlation for a few days, to allow for time zone differences
or something like that. (That's reaching back a year or more).  The
point is, in my case, the DHCP server was allocating the address to my
Win95 machine, (even though it was in conflict and even though it is
on the excluded list) and maintaining that allocation after the Win95
was re-booted.  So, after clearing out any Win95  knowledge of the
offending IP address, the NT server sensed it come back up and
dutifully re-allocated the same offending address right back to it.
Fun.

The entire sequence of events to get the address away from the
conflict was:
1.  Delete the registry key(s) noted above
2.  Use Winipcfg to release the address from RAM.
3.  Delete the reservation on the NT DHCP server.
4.  Reboot the Win95 machine.

The really comical thing?  After all this, the NT server allocated the
OTHER address on the excluded list!  I had to go into the DHCP config
and reserve those addresses for specific machines to prevent it from
giving them out!  GO NT!!

------------------------------

Date: Tue, 3 Feb 1998 14:59:53 +0000
From: Richard Letts <r.j.letts@SALFORD.AC.UK>
Subject: Re: DHCP and WIN95

>Joe, I just did some extensive research and trouble shooting on same
>and posted my results.  But, what's this tool to flush the IP
>rememberance?  That would have helped tremendously.  Natch, MS's Web
>site didn't mention it, and I've never seen it in the service paks,
>etc.

Winipcfg -- comes with every copy of windows. Sorry there's no nifty icon
on the desktop, but you can add your own shortcut.

Press the 'release all' button to release any learnt IP addresses.
press 'renew' and watch the expiry date get updated.

------------------------------

Date: Thu, 5 Mar 1998 00:58:25 +0000
From: Richard Letts <r.j.letts@SALFORD.AC.UK>
Subject: Re: VLMs with DHCP but not LWP?

Joe Doupnik wrote:
>More realistically, avoid dynamic IP pools whenever possible; they
>become a serious headache with the MS IP software around.

Not often I disagree with joe but... I've allocated over 6000 IP addresses
using bootp and/or DHCP to everything from EPOS tills and door-controllers
to pentium-II 300Mhz NT boxes. Dynamic allocation is the way to go.
[funnily enough I also use DHCP at home: that way I don't even need to
reconfigure my laptop when i plug it into the network here or at work...]

[okay, the tills were problematical, but that was due to them ignoring the
IP address in the DHCP reply, and making up their own address <GNASH>
Not even MS are *THAT* bad]

I find the management overhead of this (at most 30 minutes/day mostly
checking the packets are reaching the DHCP servers) minimal in comparison
to manually allocating IP addresses, which will no-longer work when the
lecturer takes their laptop into a lecture theatre across campus.

It takes serious arm-twisting and a letter from the Head-of-Department to
get me to assign a static IP address.

Netware 5 beta cds arrived last week, given time and a working server I'm
intending looking into the DNS/NDS/DHCP comined server to se if this will
work better that the ISC DHCP and DNS servers I run on a unix machine.
http://www.isc.org/

---------

Date: Wed, 4 Mar 1998 19:45:16 -0700
From: Joe Doupnik <JRD@CC.USU.EDU>
Subject: Re: VLMs with DHCP but not LWP?

Joe Doupnik wrote:
>>More realistically, avoid dynamic IP pools whenever possible; they
>>become a serious headache with the MS IP software around.
>
>Not often I disagree with joe but... I've allocated over 6000 IP addresses
>using bootp and/or DHCP to everything from EPOS tills and door-controllers
>to pentium-II 300Mhz NT boxes. Dynamic allocation is the way to go.
>[funnily enough I also use DHCP at home: that way I don't even need to
>reconfigure my laptop when i plug it into the network here or at work...]
>
>[okay, the tills were problematical, but that was due to them ignoring the
>IP address in the DHCP reply, and making up their own address <GNASH>
>Not even MS are *THAT* bad]

	Oh yeah? Harken back a couple of weeks to our periodic refresh of
memories on how MS networking insists upon owning an assigned IP address,
willy nilly. It is for that reason I recommend against dynamic assignments.
Manual (static) assignments are not fun to do, as I also do that chore here.

>I find the management overhead of this (at most 30 minutes/day mostly
>checking the packets are reaching the DHCP servers) minimal in comparison
>to manually allocating IP addresses, which will no-longer work when the
>lecturer takes their laptop into a lecture theatre across campus.
>
>It takes serious arm-twisting and a letter from the Head-of-Department to
>get me to assign a static IP address.
>
>netware 5 beta cds arrived last week, give time and a working server I'm
>intending looking into the DNS/NDS/DHCP comined server to se if this will
>work better that the ISC DHCP and DNS servers I run on a unix machine.
>http://www.isc.org/

	See my previous message and save yourself some frustration.
Keep Bind 8 working on that Unix machine.
	Joe D.

---------

Date: Wed, 4 Mar 1998 23:49:00 PST
From: "harrington, dana" <harrinda@MI.CC.MN.US>
Subject: Re: DHCP vs static address assignment

Here is what is happening at my site re the DHCP matter:

I administer 1000+ users on 4 networks using STATIC, BOOTP, and DHCP with
WIN3.X and WIN95, so I am very familiar with the problems.

The migration path for all networks is INW4 using DHCP.

The main EDU network is INW4 and DHCP only for about 500 boxes.
(about 60% WIN95)

I don't support static address assignments on the EDU net unless the user
can provide tons of documentation supporting the need and high level
administrative pressure (thank you richard letts for verifying I am not
the only "uncooperative" network administrator on the planet)

My INW4 DHCP EDU network is working pretty well now with minimal
administrative intervention due to all the posts i made last fall and the
responses and tips i got from the list, and i am still using service pak 3!

Minimal configuration is needed  when new boxes are installed as it is all
DHCP

In contrast, when administering the STATIC and BOOTP networks, when a new
box is installed , i need to either update the BOOTP table with the
workstation MAC address ( field tech work and typing for me) or look up what
static adresses are available ( and tell the field tech what address to use
in NET.CFG) (often, the field tech is ME)

For my site, DHCP is the only way to go as we are always adding users and
boxes

------------------------------

Date: Fri, 6 Mar 1998 20:48:58 +1100
From: Daryl Maunder <dmaunder@MIDNIGHTOIL.COM.AU>
Subject: Re: VLMs with DHCP but not LWP?

>>More realistically, avoid dynamic IP pools whenever possible; they
>>become a serious headache with the MS IP software around.
>
>Not often I disagree with JoeD but...I've allocated over 6000 IP addresses
>using bootp and/or DHCP to everything from EPOS tills and door-controllers
>to pentium-II 300Mhz NT boxes. Dynamic allocation is the way to go.
>[funnily enough I also use DHCP at home: that way I don't even need to
>reconfigure my laptop when i plug it into the network here or at work...]

Not often anyone disagrees with Joe for that matter, but I couldn't agree
with Richard more on this one. We are running Novell BootP server (not
DHCP) with 25,000 plus clients, and a mix of clients includinf NETX/VLM
with DOS TCPIP.EXE and Client32/Dos, and some Win95/WinNT using billgpc,
the bootp client for those platforms. It isnt a perfect world, and we have
had more than our share of problems with the Novell bootp servers, but it
sure beats the heck out of managing that many statically addressed clients.

In regard to the original question, to make the DOS TCP stack use Bootp,
you just remove the ip_address etc lines in the PROTOTCOL TCPIP section.

This is one configured statically:

Protocol TCPIP
   PATH TCP_CFG J:\ETC\TCP
   ip_address   203.27.234.4
   ip_netmask   255.255.255.224
   ip_router    203.27.234.1

To make it use Bootp, remove the 3 lines starting with ip_ and all will be
happy.

------------------------------

Date: Fri, 27 Mar 1998 16:22:50 -0700
From: Joe Doupnik <JRD@CC.USU.EDU>
Subject: Re: DHCP and VLMs

>>Can someone tell me if the VLM's support DHCP and if so, how to
>>implement it. I am moving to the new client, but wanted to do it more
>>gradually if possible
>
>I run a NetWare and NT-based shop.  The clients have a mixture of VLMs
>and Client32 on Windows 3.1-95.  On the windows 3.11 workstation (3.1 has
>no such DHCP client), they all work fine, 'cept when the NT box goes
>down. That hoses the DHCP server.
>
>I imagine that NetWare has a more stable DHCP server.   So, it should
>present no problem.  DHCP on the wire is just an advertisement, nothin
>else, right?
--------

	Fellas, IPX has nothing, zero, to do with TCP/IP. It's a different
protocol suite. VLMs support only IPX, and has nothing, zero, to do with
TCP/IP. NETX does IPX only. Under that IPX support resides ODI, typically,
which is a packet handler, not a protocol stack. IPXODI uses ODI, a TCP/IP
stack can use ODI, many things can use ODI and not involve IPX at all.
A picture:

	IPX apps                TCP/IP apps         Other apps
	  |                         |                     |
	VLMs or C32 or NETX     TCP/IP stack        Other protocols
	IPXODI                      |                     |
	  |                         |                     |
	 ---------------------------------------------------------
			ODI
	 ---------------------------------------------------------
			lan adapter hardware
	 ---------------------------------------------------------
			wire/glass

	Next piece of the puzzle. DHCP is for TCP/IP, not IPX. It is a
TCP/IP application. There is no service advertizing protocol involved at
all and no advertizing at all. DHCP runs on top of an existing TCP/IP stack,
and the interfacing depends on which TCP/IP stack is used. A TCP/IP stack
does not need IPX loaded, and hence no IPXODI et al, and no VLMs either.
	If you don't understand DHCP then a) you have lots of company,
b) please read the RFCs, c) monitor the wire of a properly working DHCP
setup as a self check.
	Last piece. Microsoft's impression of TCP/IP is wierd so trust not
that material.
	Joe D.

------------------------------

