DHCPNACK Message-IP Address Denied

  • Thread starter Thread starter Milt
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Milt

My Comcast broadband cable access has failed for an hour or two several times
in the last month. Comcast is of no help.

When it fails, my modem power, receive and pc activity lamps are on. The
send lamp is flashing. And the on line lamp is off. I've tried removing the
router and connecting the modem directly to my computer. And I've tried
rebooting. Neither action restores my connection. If I do nothing, the
connection restores itself in an hour or two.


I looked in Windows Event Viewer/System/ Properties. I find this error
message:
"The IP address lease 192.168.1.2 for the Network Card with network address
0080AD7XXXXXX has been denied by the DHCP server 0.0.0.0. {The DHCP Server
sent a DHCPNACK message}."


As I read the error message, it seems to say that Comcast's server is the
problem.
Is that correct?

Thanks,
Milt
 
My Comcast broadband cable access has failed for an hour or two
several times in the last month. Comcast is of no help.

When it fails, my modem power, receive and pc activity lamps are
on. The send lamp is flashing. And the on line lamp is off. I've
tried removing the router and connecting the modem directly to my
computer. And I've tried rebooting. Neither action restores my
connection.
Click to expand...

Cable modems are typically configured to only give out one IP address
to one device. If you have a router connected to the modem, then the
router gets that IP address. If you disconnect the router and
connect the computer directly to your modem, the modem sees a 2nd
device and won't give out an address unless the modem is unplugged
from the wall power then repowered -- in which case the first device
it sees gets the IP address. (i.e. Power cycle the modem, not the
computer).

I looked in Windows Event Viewer/System/ Properties. I find this
error message:
"The IP address lease 192.168.1.2 for the Network Card with
network address 0080AD7XXXXXX has been denied by the DHCP server
0.0.0.0. {The DHCP Server sent a DHCPNACK message}."
As I read the error message, it seems to say that Comcast's server
is the problem.
Click to expand...

When a computer negotiates for an IP address, it sometimes takes a
shortcut step of saying "Last time I had IP address XXX.XXX.XXX.XXX"
to the DHCP server in hopes of getting the same address. If, for
whatever reason the DHCP server doesn't like this address, it will
negotiate an alternate address and this error appears in the Event
log. This error is perfectly normal and shouldn't be a concern. In
your case, this error originates in a DHCP negotiation between your
computer and your router -- not the modem or your ISP. This error
would be expected if you disconnect your computer from your router
and connect it directly to the modem as the modem would not give out
a 192.168.x.x address.
If I do nothing, the connection restores itself in an
hour or two.
Click to expand...

More than likely, there was just a disruption in service which was
corrected during that time.

HTH,
John
 
I have a client who is getting these same error messages. In his case, all
Internet access from his office is blocked, and rebooting the router is the
only thing that restores it. At times corresponding to these outages, two
different computers get these errors, a few seconds apart:

"Your computer was not able to renew its address from the network (from the
DHCP Server) for the Network Card with network address 001731474566. The
following error occurred:
The operation was canceled by the user. . Your computer will continue to try
and obtain an address on its own from the network address (DHCP) server."

followed three seconds later by:

The IP address lease 192.168.1.101 for the Network Card with network address
001731474566 has been denied by the DHCP server 0.0.0.0 (The DHCP Server sent
a DHCPNACK message).

Of course, the network address is not the same for the two computers.

Following the events that cause these errors, no computer on the network has
Internet access anymore, until the router is restarted. Thus, the
explanation that this is normal and that the computers will just get a
different IP address doesn't seem to apply. Also, I should note that these
system events are classified as errors, not as warnings or information, which
it would seem that they would be if it were actually normal.

I will be doing more research on this matter in the Cisco support system, as
the router in question is a Linksys RV106. And yes, I've updated its
firmware to the latest revision.
 
Hi
Try to set the computers with Static DHCP (I.e., the Router should assign
upon renewal the same IP as before to each computer).
Check the leasing time of the DHCP and make as long as possible.
The RV 016 should have instructions for this actions.
Jack (MS, MVP-Networking).
 
Jack -

Thanks for the quick response. I'm on the client site right now, and I have
new information.

One thing is that we are now seeing this problem multiple times per day,
whereas the DHCP lease time is set for 24 hours. Also, when the computer
does get a new lease, after restarting the router, it's the same address as
before.

The other thing to note is that this is started happening just last week,
though the network configuration, DHCP setup, etc., hasn't changed. At
first, the client thought the problem was related to the DSL line itself, so
had an AT&T tech come out to look. They replaced the DSL modem, for no
reason that I can see.

Changing the DHCP lease time is simple on this router, but I don't think it
will help, given that the error occurs well before the lease has expired.

I would suspect a hardware problem with the PC's network interface, except
for the fact that the errors occur pretty much simultaneously on two machines
at once. This, of course, points to the router.

Again, I appreciate the response. If you have any other ideas, I'd be happy
to hear them, as I'm baffled so far. I'll be pursuing the router angle and
will report back to this thread if I find an answer.
 
Thanks for the quick response. I'm on the client site right now,
and I have new information.

One thing is that we are now seeing this problem multiple times
per day, whereas the DHCP lease time is set for 24 hours. Also,
when the computer does get a new lease, after restarting the
router, it's the same address as before.

The other thing to note is that this is started happening just
last week, though the network configuration, DHCP setup, etc.,
hasn't changed. At first, the client thought the problem was
related to the DSL line itself, so had an AT&T tech come out to
look. They replaced the DSL modem, for no reason that I can see.

Changing the DHCP lease time is simple on this router, but I don't
think it will help, given that the error occurs well before the
lease has expired.
Click to expand...

Being that resetting the router temporarily fixes the problem plus that
multiple machines on the subnet are affected points squarely at the
router itself. First, I would try a Factory Reset on the router
(usually hold the reset button down for 10 seconds while powered up),
then I would check the router manufacturer's website for router
firmware upgrades and if that doesn't help, then swap out the router.

HTH,
John
 
Agreed. The router is the obvious culprit, though I had to consider the
possibility that the PCs were doing something that was corrupting the routers
DHCP clients table or something like that.

I've been avoiding doing the factory reset on the router, but it's a good
suggestion.
 
Hi
I agree it might be time for new Router, or RMA this one if it is under some
sort of warrantee / service contract.
Jack (MS, MVP-Networking).
 
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