Subject: Help, DHCP Server on WinNT!!!

From: [email-masked] (by way of Ralph Droms <[email-masked]>)
Date: Fri, 30 Jul 1999 10:22:10 -0400 (EDT)

message sent to [email-masked] by [email-masked] follows.
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Hi,

I have a problem. In short:

1 DHCP (MS WinNT) server for LAN (local subnet), one router to other LAN's,
3 3com hubs and servers are connected to 3com switch. Clients can't obtain
IP configuration from DHCP server. In DHCP administrator window I can see
only offered adreses (there is no computer names) for a new clients, theris
no intact for old valid leases . Leases are set for 3 days, but these new
leases always are expired. Clients (Win9X, WinNT) are claiming: "DHCP error.
Can't obtain IP address". So, I enabled the second DHCP server (for new
address poll ), it was on the same situation. IMO, It looks like something
intercepts an DHCPOFFER.
Till today (about 1 year) was no problem.
Can You give me some suggestions?

Regards
Gintautas Kepalas
Network Administrator
ELSIS
tel: +3707 310488
mob: +37089 20454

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From: Steve Gonczi <[email-masked]>
Date: Fri, 30 Jul 1999 11:10:47 -0400 (EDT)

Are the clients on the same segment where your server is, 
or is there a router between them?

If the router sits in between, someone may have messed up your
bootp relay setup.

If things were working fine for a year, and not working now,
you must look for something that has recently changed.

If I had to troubleshoot this, I would want to see packet traffic
to/from your server.

sG
-----Original Message-----
From: [email-masked] [mailto:[email-masked]]
Sent: Friday, July 30, 1999 10:22 AM
To: Multiple recipients of list
Subject: Help, DHCP Server on WinNT!!!

Regards
Gintautas Kepalas
Network Administrator
ELSIS
tel: +3707 310488
mob: +37089 20454

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From: Jay Morin <[email-masked]>
Date: Fri, 30 Jul 1999 11:59:23 -0400 (EDT)

Check for a DHCP RELAY on the router.  The discover/offer maybe getting dropped
there.

--
Jay Morin
LAN Administrator
Andover Service Center
(978)474-5678 [Phone]
(978)474-9699 [FAX]
Mailto:[email-masked]

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From: Ted Lemon <[email-masked]>
Date: Fri, 30 Jul 1999 12:02:01 -0400 (EDT)

Two things.   First, there is now a mailing list for asking questions
like this: [email-masked].   This mailing list is technically
for discussion of the protocol, not for asking for help with existing
applications.   Your question is kind of both, so I am not saying that
it's inappropriate here - just letting you know about the other
mailing list.

As to your question, if things were working for a long time and then
suddenly stopped, my first instinct would be to assume that a new DHCP
server that is not configured correctly has been added to your network
without your knowledge.   Adding a third server didn't help you
because the second, unknown server is still out there poisoning your
network.   This is just a guess, of course - I may be completely
wrong.

To find out, I would suggest that you start up a packet sniffer to
look for DHCP packets, and then start a client and have it request an
address.   Look for two things: how does the protocol go (what packets
are exchanged) and who sent them?   If, for example, you see DHCPNAK
packets coming from some unknown IP address, that's your rogue
server.

If this doesn't help you, please follow up with whatever you have
learned on the dhcp-interest mailing list, and we'll try to help you
solve this problem.   To subscribe, send mail to
[email-masked] with "subscribe" in the subject line.

Best of luck!

			       _MelloN_