IP conflict (DHCP assigned) when hibernating on home network

I have been researching postings about IP conflicts using DHCP. Although
there are tons of such postings, most have to do with mixing DHCP with
static IPs, or with split-second timing problems, or with clearing IP
conflicts after they have occurred.



I suspect that my IP conflicts are related to leases expiring and IP
addresses being reassigned while the original lessee is hibernating.



This is a home network with a cable-modem and a router that serves as my
DHCP server. There are no static IP addresses in the DHCP IP pool range.
Computers in my house are typically hibernated rather than shut down, so
that work in progress can be left open, and so that the computers power on
faster.



I have had intermittent IP conflicts with my old, wired Linksys router. I
eliminated that problem by setting the IP lease length to three years.



My new router is a wireless Netgear, with both wired ports and wireless
connections. This may complicate things a little for two reasons: (1) the
Netgear router does not have a setting to allow one to change the IP lease
length, and the lease length is pretty short, and (2) the same computer
might have one wireless connection and one wired connection. I prefer to
keep wireless disabled for increased security and higher bandwidth, but it
is often convenient to use wireless.



However, the problem still occurred with the old, wired-only router.



My network is a mix of Windows XP, Windows 2000, and Linux-based appliances
(a pocket print-server appliance and a TiVo).



Will an expired IP lease be discovered on waking from hibernation? Could
hibernation be the problem? Or is there some other issue that I should be
looking at?



- David

Go into your router's setup and see if you can reserve each IP address for
each computer. Tell the router the proffered IP for each computer. Usually
done via the MAC code. It should be fairly obvious but if you need more help
repost with the make model of router.
--
Please repost if you find the fault

Glen P
~~~~~~~~~~~~~~~~~~~~~
"David D." <daviddiamond.remove-if-not-(E-Mail Removed)> wrote in message
news:(E-Mail Removed). ..
>I have been researching postings about IP conflicts using DHCP. Although
> there are tons of such postings, most have to do with mixing DHCP with
> static IPs, or with split-second timing problems, or with clearing IP
> conflicts after they have occurred.
>
>
>
> I suspect that my IP conflicts are related to leases expiring and IP
> addresses being reassigned while the original lessee is hibernating.
>
>
>
> This is a home network with a cable-modem and a router that serves as my
> DHCP server. There are no static IP addresses in the DHCP IP pool range.
> Computers in my house are typically hibernated rather than shut down, so
> that work in progress can be left open, and so that the computers power on
> faster.
>
>
>
> I have had intermittent IP conflicts with my old, wired Linksys router. I
> eliminated that problem by setting the IP lease length to three years.
>
>
>
> My new router is a wireless Netgear, with both wired ports and wireless
> connections. This may complicate things a little for two reasons: (1)
> the
> Netgear router does not have a setting to allow one to change the IP lease
> length, and the lease length is pretty short, and (2) the same computer
> might have one wireless connection and one wired connection. I prefer to
> keep wireless disabled for increased security and higher bandwidth, but it
> is often convenient to use wireless.
>
>
>
> However, the problem still occurred with the old, wired-only router.
>
>
>
> My network is a mix of Windows XP, Windows 2000, and Linux-based
> appliances
> (a pocket print-server appliance and a TiVo).
>
>
>
> Will an expired IP lease be discovered on waking from hibernation? Could
> hibernation be the problem? Or is there some other issue that I should be
> looking at?
>
>
>
> - David
>
>
>
>
>
>
>
>

Thanks, Glen.

I will take a look. I know that my router (Netgear WGR614) offers
MAC-based security. I will look to see if it also has preferred IP by MAC
address.

I set up the router with WPA security. I do not know if I need to turn
off WPA in order to use MAC security, but I will explore the related admin
menus and let you know how I make out.

I would still be interested in knowing the cause of my IP conflicts.
Netgear tech support told me that I cannot get IP conflicts by hibernating
computers, that the router will handle everything correctly. I am not
convinced that that is the case. For example, what happens to Browser
sessions that span the hibernation? I suggested a firmware upgrade to
allow one to set the IP lease duration, in order to solve the IP conflict
problem via a long lease. Their response was essentially that there is no
problem.

- David
~~~~~~~~~~~~~~~~~~~~~~


"Glen" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> Go into your router's setup and see if you can reserve each IP address for
> each computer. Tell the router the proffered IP for each computer. Usually
> done via the MAC code. It should be fairly obvious but if you need more
help
> repost with the make model of router.
> --
> Please repost if you find the fault
>
> Glen P
> ~~~~~~~~~~~~~~~~~~~~~

On Thu, 13 Jul 2006 14:07:49 -0400, David D. wrote:

<snip>
>
> Will an expired IP lease be discovered on waking from hibernation? Could
> hibernation be the problem? Or is there some other issue that I should be
> looking at?
>
>
>
> - David

In your power management settings ensure that your NIC is not powered off
when your computer goes into hibernation. ll my computers retain network
connectivity even when in hibernation mode.

When you start a computer it gets assigned an IP, eg 192.168.0.2 from the
router. When it hibernates it effectively shuts down. Windows as it was
running is stored in the hibernating file. When another computer on the
network starts up, the router, thinking the previous IP is now free (because
the hibernating computer is effectively shut down) assignees 192.168.0.2 to
the computer just starting up. When the hibernating computer wakes up it
already thinks it has the right to use 192.168.0.2 because as far as its
concerned it was given to it and it hasn't given it up. Hence the conflict.
--
Please repost if you find the fault

Glen P
~~~~~~~~~~~~~~~~~~~~~
"David D." <daviddiamond.remove-if-not-(E-Mail Removed)> wrote in message
news:(E-Mail Removed). ..
> Thanks, Glen.
>
> I will take a look. I know that my router (Netgear WGR614) offers
> MAC-based security. I will look to see if it also has preferred IP by MAC
> address.
>
> I set up the router with WPA security. I do not know if I need to
> turn
> off WPA in order to use MAC security, but I will explore the related admin
> menus and let you know how I make out.
>
> I would still be interested in knowing the cause of my IP conflicts.
> Netgear tech support told me that I cannot get IP conflicts by hibernating
> computers, that the router will handle everything correctly. I am not
> convinced that that is the case. For example, what happens to Browser
> sessions that span the hibernation? I suggested a firmware upgrade to
> allow one to set the IP lease duration, in order to solve the IP conflict
> problem via a long lease. Their response was essentially that there is
> no
> problem.
>
> - David
> ~~~~~~~~~~~~~~~~~~~~~~
>
>
> "Glen" <(E-Mail Removed)> wrote in message
> news:(E-Mail Removed)...
>> Go into your router's setup and see if you can reserve each IP address
>> for
>> each computer. Tell the router the proffered IP for each computer.
>> Usually
>> done via the MAC code. It should be fairly obvious but if you need more
> help
>> repost with the make model of router.
>> --
>> Please repost if you find the fault
>>
>> Glen P
>> ~~~~~~~~~~~~~~~~~~~~~
>
>

> "Glen" <(E-Mail Removed)> wrote in message:
> > Go into your router's setup and see if you can reserve each IP address
for
> > each computer. Tell the router the proffered IP for each computer.
Usually
> > done via the MAC code. It should be fairly obvious but if you need more
> help repost with the make model of router.
> > Glen P


Glen,

Thanks for the tip about the router setting for reserved IP address by
MAC address.

The Netgear WGR614's configuration menus are well designed. I did not
even have to type in the MAC, IP and computer names. They were prefilled
for me. All I needed to do was to click a radio button.

David