NDIS 5.1 IM Driver on Windows Server 2008 failing after sleep

Hello,
I have observed a strange behavior with NDIS 5.1 IM drivers on Windows 2008
servers.
If a server has a NDIS 5.1 IM driver installed and is sent to sleep and
woken up, Active connections "hang" and disconnect after a while.

Steps to reproduce:

1. Install passthru sample on a Windows 2008 Server.
2. Connect to the server using telnet or any other service that allows you
to keep the connection alive.
3. Send the computer to sleep (Regular sleep, Not hibernate).
4. Wake the server up.
5. Try to send data from the client to the server. - Fail

This exact procedure works both when there is no IM driver installed or when
using LWF drivers.

Is there a workaround for this issue for 5.1 drivers?

Thanks.
Sasha.

IIRC, when NDIS 5 IM filters are run on NDIS 6 platforms then during
transitions to low-power states NDIS will unbind its bindings. Of course,
one side-effect of unbinding will be that the binding becomes disconnected.
TCP/IP would notice this and naturally abort the existing connection.

On return from low-power states NDIS 6 re-establishes the NDIS 5 IM filter
bindings and the IM filter's virtual adapter would become connected again.

NDIS 6 filters behave differently on power transitions. There is no
"unbinding". Instead members of a stack are "paused" and later restarted;
this is pretty smooth.

Sounds like the scenario you are mentioning is a little artificial. Even
with NDIS 6 filters I would expect that if the Sleep was long enough (which
it probably would be in "real life") the connections would timeout anyway.

If the NDIS 5 IM filter behavior is a problem for you the best solution is
to make a NDIS 6 filter.

Good luck,

Thomas F. Divine



"Sasha Levin" <Sasha > wrote in message
news:F12EE564-4788-4DC5-9264-...
> Hello,
> I have observed a strange behavior with NDIS 5.1 IM drivers on Windows
> 2008
> servers.
> If a server has a NDIS 5.1 IM driver installed and is sent to sleep and
> woken up, Active connections "hang" and disconnect after a while.
>
> Steps to reproduce:
>
> 1. Install passthru sample on a Windows 2008 Server.
> 2. Connect to the server using telnet or any other service that allows you
> to keep the connection alive.
> 3. Send the computer to sleep (Regular sleep, Not hibernate).
> 4. Wake the server up.
> 5. Try to send data from the client to the server. - Fail
>
> This exact procedure works both when there is no IM driver installed or
> when
> using LWF drivers.
>
> Is there a workaround for this issue for 5.1 drivers?
>
> Thanks.
> Sasha.
>

Hello,
From what I understand, TCP/IP connections on the new (Windows 2008, etc')
stack don't disconnect even if their underlying interface is dropped, Which
means that I can disable the interface, reconnect it and the connection keeps
working - something which I've tested.

In my case, After the computer wakes up from sleep I can still see the
connection if I do 'netstat' and I don't get RST packets for incoming packets
on that connection, I just don't get any outgoing packets.

I've made a NDIS 6 LWF driver that does what I need, It's just that the
behavior for NDIS 5.1 IM drivers is rather weird and looks buggy.

Thanks.
Sasha.

"Thomas F. Divine" wrote:

> IIRC, when NDIS 5 IM filters are run on NDIS 6 platforms then during
> transitions to low-power states NDIS will unbind its bindings. Of course,
> one side-effect of unbinding will be that the binding becomes disconnected.
> TCP/IP would notice this and naturally abort the existing connection.
>
> On return from low-power states NDIS 6 re-establishes the NDIS 5 IM filter
> bindings and the IM filter's virtual adapter would become connected again.
>
> NDIS 6 filters behave differently on power transitions. There is no
> "unbinding". Instead members of a stack are "paused" and later restarted;
> this is pretty smooth.
>
> Sounds like the scenario you are mentioning is a little artificial. Even
> with NDIS 6 filters I would expect that if the Sleep was long enough (which
> it probably would be in "real life") the connections would timeout anyway.
>
> If the NDIS 5 IM filter behavior is a problem for you the best solution is
> to make a NDIS 6 filter.
>
> Good luck,
>
> Thomas F. Divine
>
>
>
> "Sasha Levin" <Sasha > wrote in message
> news:F12EE564-4788-4DC5-9264-...
> > Hello,
> > I have observed a strange behavior with NDIS 5.1 IM drivers on Windows
> > 2008
> > servers.
> > If a server has a NDIS 5.1 IM driver installed and is sent to sleep and
> > woken up, Active connections "hang" and disconnect after a while.
> >
> > Steps to reproduce:
> >
> > 1. Install passthru sample on a Windows 2008 Server.
> > 2. Connect to the server using telnet or any other service that allows you
> > to keep the connection alive.
> > 3. Send the computer to sleep (Regular sleep, Not hibernate).
> > 4. Wake the server up.
> > 5. Try to send data from the client to the server. - Fail
> >
> > This exact procedure works both when there is no IM driver installed or
> > when
> > using LWF drivers.
> >
> > Is there a workaround for this issue for 5.1 drivers?
> >
> > Thanks.
> > Sasha.
> >

I've tried writing a small echo server and got a rather interesting result:
Once the server wakes up from a sleep, It receives a packet from a client
perfectly (without ACKing it). When it calls the send() function to send it
back, send returns a good result indicating it sent the entire buffer.
The problem is that the packet never leaves the TCP/IP stack (doesn't even
show on wireshark).