A Microsoft version of DHCP client computer cannot obtain an IP address from a server that is running Linux

Frank Stanek frank.stanek at est.fujitsu.com
Tue Mar 22 11:37:10 UTC 2011


this is not happening in our segments:
When we change a Windows client to another segment, it sends a 
DHCPREQUEST with its old address. The DHCP server replies with DHCPNAK 
(wrong network). After that, a normal DHCP "handshake" immediately 

So I'm guessing your Servers should send a DHCPNAK immediately after the 
first REQUEST. Are your DHCP servers authoritative for their 
segments/subnets (authoritative;-statement)?

The dhcpd.conf manual page says this:
> If the address is no longer available, or the client isn't permitted 
to have it, the server will send a DHCPNAK (you want this). If the 
server knows nothing about the address, it will remain silent (this 
might be your case), unless the address is incorrect for the network 
segment to which the client has been attached and the server is 
authoritative (!) for that network segment, in which case the server 
will send a DHCPNAK even though it doesn't know about the address.

Just a thought, but maybe it helps.


-----Original Message-----
From: sunliang [mailto:sunliang at cn.fujitsu.com] 
Sent: Montag, 21. März 2011 02:24
To: dhcp-users at lists.isc.org
Subject: A Microsoft version of DHCP client computer cannot obtain an IP 
address from a server that is running Linux


I am having a problem explaining as below:

Under the DHCP environment in which using three segments to process the
IP leasing, after the client accepts the IP leasing and turns to dynamic
status, the IP address of the destination of IP leasing will fail when
we transfer the client to other segments without doubts. After resetting
the LAN cable, the IP leasing will process successfully.

Some description about my environment:
OS : Red Hat Enterprise Linux 5.3 (for x86)

RPM: dhcp-3.0.5-18.el5 (RHEL 5.3 Standard RPM)

When transferring the PC client node (WindowsXP) to other segments, the
problem cited above occurs.

1. Without releasing, the client of leasing 137segment’s ending IP
address transfers to 138segment’s ending directly.

2. When LAN cable connects to the client, the IP address of 137segment
seems to be distributed. However, it fails eventually.

169.254.x.x(LINKLOCAL) is distributed

Only connect to the LAN cable. Hand free.

3. Reconnect to the LAN cable after a few seconds; the IP address of
138segment is leased.Only reconnect to the LAN cable, hand free.

※If only with the connection to the LAN cable, the IP address of
138segment will not be leased.

After digesting related documents, I noticed that the reason why this
problem occurs is that the client PC has sent three DHCP addresses of
discovering and requesting message.

Set the IP address of client PC as previous one. The DHCP client PC will
send three DHCP discovering messages.

For details, please refer to http://support.microsoft.com/kb/835304/en

But what still confuses me is how the Linux DHCP server setting ignores
these “repeated” DHCP discovering messages. And how can I solve this

I hope you guys can help me with it and share your points of views.


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