I am having an intermittent problem with DCOM that the readers of the 
microsoft.public.programmer.ole newsgroup have not been able to offer any 
suggestions on (other than call Microsoft PSS). Since it is intermittent, it 
is difficult to know what to look for or what to ask for from Microsoft PSS. 
It happens about once a week and, each time, I have attempted to do some 
research and debugging to learn more. I am now thinking it is more network 
or RPC related than DCOM related.

I have a client application that calls a server application using DCOM. It 
passes four interfaces. The server application calls those interfaces are 
regular intervals, ie. calls back the client application. So technically the 
client application is also a DCOM server.

Intermittently, the first call from the server application to the client 
application returns E_NOINTERFACE without even entering the client 
application code. It must be happening somewhere in the DCOM/RPC/networking 
internals. Once this happens, all calls from the server application to the 
client application consistently fail similarly and repeatedly, even if both 
applications are restarted, until the client is rebooted.

All threads involved entered a Multi-Threaded Apartment (MTA), which 
simplifies things by eliminating the possibility that something goofy is 
happening with STA and messages.

The client application runs on Windows XP Professional Service Pack 2 and 
the server application runs on Windows Server 2003 Service Pack 1.

Could the E_NOINTERFACE error be related to network connectivity? While "net 
session" normally shows no or very few sessons, "nbtstat -a" shows TCP and 
UDP connections to at least half a dozen servers and I have seen it get up 
to twelve. I know that Windows XP Professional has a limit of 10 inbound 
connections, but what defines a connection? It is not clear to me from this 
KB article or other documentation:

http://support.microsoft.com/kb/314882/en-us

I tried to reproduce the problem by having ten computers use FTP to connect 
to my Windows XP Professional machine and sit at the logon prompt, tying up 
the connections. I saw those connections in MMC and "nbtstat -a". There were 
no connections of any kind to the machine running the server application at 
that point. I then used DCOM. It connected just fine and behaved normally. 
There was no E_NOINTERFACE error.

Thanks,

Paul

Excuse me, where I refer to "nbtstat -a", I mean to refer to "netstat -a".

"Paul Baker [MVP, Windows - Networking]" <paulrichardbaker@community.nospam> 
wrote in message news:eufPjOdVHHA.1200@TK2MSFTNGP04.phx.gbl...
> "nbtstat -a" shows TCP and  UDP connections

"Paul Baker [MVP, Windows - Networking]" <paulrichardbaker@community.nospam>
wrote in message news:uvuq8vdVHHA.392@TK2MSFTNGP06.phx.gbl...
> Excuse me, where I refer to "nbtstat -a", I mean to refer to "netstat -a".
>
> "Paul Baker [MVP, Windows - Networking]"
<paulrichardbaker@community.nospam>
> wrote in message news:eufPjOdVHHA.1200@TK2MSFTNGP04.phx.gbl...
> > "nbtstat -a" shows TCP and  UDP connections
>
>

The "10 connection limit" is widely misunderstood, since that phrase is used
to describe a variety of completely different topics.  To understand the
misunderstanding, remember to distinguish between sockets and services.
Sockets are what you see from netstat.  Services relate to things like file
sharing and print sharing.  Services might be implemented using sockets, but
with respect to this "10 connection limit" discussion, they are still
different.

For services, there is a connection limit imposed by the OS: 5 connections
for XP Home and 10 for XP Pro.  Thus, you cannot try to share files on a
semi-large SOHO-style network, for the reason that the 10 connection limit
is quickly reached.

For sockets, there is no limit on the number of inbound connections.
Actually, there is a legal limit that's defined in the Windows end-user
license agreement, and that number is 10.  Accordingly, if you are using a
product from Microsoft, like IIS, then the limit is imposed by the product
itself (presumably because the product was writtten by Microsoft and MS
actually tries to abide by its own EULA).  But if you are using 3rd party
products, or writing something on your own, there is no limit, and the OS
itself does not try to enforce the EULA limit.  Many users have reported
that they successfully manage 1,000's of simultaneous incoming socket
connections, even on XP Home systems.

There is also no limit on outbound socket connections.  SP2 changed the TCP
stack, and there is now a limit on outbound connections that are
*half-open*.  The limit is 10, but half-open connections are not the same
thing as established connections.  Half-open refers to a connection that has
not completed TCP's three-way handshake.  The three-way handshake requires
SYN, SYN-ACK and ACK, and in a half-open connection, the SYN has been sent
but the SYN-ACK has not yet been received.  There can only be 10 half-open
connections in this state.  Once the three-way handshake has been completed,
then the connection is established, and there is no limit on the number of
established connections.  (The intent of the SP2 change was to slow down the
rate at which new connections are established, but not to limit the number
of actual connections.)

With the above in mind, I don't think that your FTP connections are
stressing the computer in the right way.  Try sharing files with 10
different computers, to see if this produces your E_NOINTERFACE symptoms.

Mike

Additionally : Once 
http://support.microsoft.com/default.aspx?scid=kb;en-us;314882 looked 
exactly as
http://support.microsoft.com/?scid=kb;EN-US;122920 where sockes counted into 
number of limited sessions which is incorrect ( you can check that by 
opening IE much more than 10 times :) ) and documentation corrected now as 
needed ( only SMB and pipe connections counted ). The number of connections 
in MSFT tests published ( depends of free resources of computer ) was around 
50,000 on W2K
Arkady

"Michael K. O'Neill"  wrote in message 
news:epAmgreVHHA.1432@TK2MSFTNGP02.phx.gbl...
>
> "Paul Baker [MVP, Windows - Networking]" 
> <paulrichardbaker@community.nospam>
> wrote in message news:uvuq8vdVHHA.392@TK2MSFTNGP06.phx.gbl...
>> Excuse me, where I refer to "nbtstat -a", I mean to refer to 
>> "netstat -a".
>>
>> "Paul Baker [MVP, Windows - Networking]"
> <paulrichardbaker@community.nospam>
>> wrote in message news:eufPjOdVHHA.1200@TK2MSFTNGP04.phx.gbl...
>> > "nbtstat -a" shows TCP and  UDP connections
>>
>>
>
> The "10 connection limit" is widely misunderstood, since that phrase is 
> used
> to describe a variety of completely different topics.  To understand the
> misunderstanding, remember to distinguish between sockets and services.
> Sockets are what you see from netstat.  Services relate to things like 
> file
> sharing and print sharing.  Services might be implemented using sockets, 
> but
> with respect to this "10 connection limit" discussion, they are still
> different.
>
> For services, there is a connection limit imposed by the OS: 5 connections
> for XP Home and 10 for XP Pro.  Thus, you cannot try to share files on a
> semi-large SOHO-style network, for the reason that the 10 connection limit
> is quickly reached.
>
> For sockets, there is no limit on the number of inbound connections.
> Actually, there is a legal limit that's defined in the Windows end-user
> license agreement, and that number is 10.  Accordingly, if you are using a
> product from Microsoft, like IIS, then the limit is imposed by the product
> itself (presumably because the product was writtten by Microsoft and MS
> actually tries to abide by its own EULA).  But if you are using 3rd party
> products, or writing something on your own, there is no limit, and the OS
> itself does not try to enforce the EULA limit.  Many users have reported
> that they successfully manage 1,000's of simultaneous incoming socket
> connections, even on XP Home systems.
>
> There is also no limit on outbound socket connections.  SP2 changed the 
> TCP
> stack, and there is now a limit on outbound connections that are
> *half-open*.  The limit is 10, but half-open connections are not the same
> thing as established connections.  Half-open refers to a connection that 
> has
> not completed TCP's three-way handshake.  The three-way handshake requires
> SYN, SYN-ACK and ACK, and in a half-open connection, the SYN has been sent
> but the SYN-ACK has not yet been received.  There can only be 10 half-open
> connections in this state.  Once the three-way handshake has been 
> completed,
> then the connection is established, and there is no limit on the number of
> established connections.  (The intent of the SP2 change was to slow down 
> the
> rate at which new connections are established, but not to limit the number
> of actual connections.)
>
> With the above in mind, I don't think that your FTP connections are
> stressing the computer in the right way.  Try sharing files with 10
> different computers, to see if this produces your E_NOINTERFACE symptoms.
>
> Mike
>
>

Thank to you both.

Is there a way I can reliably identify the number of inbound connections for 
the purpose of this limit? I am not knowledgeable enough to entirely 
understand the output of netstat, recognize the port numbers, etc.

What actions are the easiest way to make a connection for file and printer 
sharing and how do I ensure that I can have 10 inbound connections for file 
or printer sharing without them timing out? How do I know if they're active? 
(I am not particularly knowledgeable about this stuff despite my MVP title).

Thanks,

Paul

"Arkady Frenkel"  wrote in message 
news:uG$vVOlVHHA.4796@TK2MSFTNGP05.phx.gbl...
> Additionally : Once 
> http://support.microsoft.com/default.aspx?scid=kb;en-us;314882 looked 
> exactly as
> http://support.microsoft.com/?scid=kb;EN-US;122920 where sockes counted 
> into number of limited sessions which is incorrect ( you can check that by 
> opening IE much more than 10 times :) ) and documentation corrected now as 
> needed ( only SMB and pipe connections counted ). The number of 
> connections in MSFT tests published ( depends of free resources of 
> computer ) was around 50,000 on W2K
> Arkady
>
> "Michael K. O'Neill"  wrote in message 
> news:epAmgreVHHA.1432@TK2MSFTNGP02.phx.gbl...
>>
>> "Paul Baker [MVP, Windows - Networking]" 
>> <paulrichardbaker@community.nospam>
>> wrote in message news:uvuq8vdVHHA.392@TK2MSFTNGP06.phx.gbl...
>>> Excuse me, where I refer to "nbtstat -a", I mean to refer to 
>>> "netstat -a".
>>>
>>> "Paul Baker [MVP, Windows - Networking]"
>> <paulrichardbaker@community.nospam>
>>> wrote in message news:eufPjOdVHHA.1200@TK2MSFTNGP04.phx.gbl...
>>> > "nbtstat -a" shows TCP and  UDP connections
>>>
>>>
>>
>> The "10 connection limit" is widely misunderstood, since that phrase is 
>> used
>> to describe a variety of completely different topics.  To understand the
>> misunderstanding, remember to distinguish between sockets and services.
>> Sockets are what you see from netstat.  Services relate to things like 
>> file
>> sharing and print sharing.  Services might be implemented using sockets, 
>> but
>> with respect to this "10 connection limit" discussion, they are still
>> different.
>>
>> For services, there is a connection limit imposed by the OS: 5 
>> connections
>> for XP Home and 10 for XP Pro.  Thus, you cannot try to share files on a
>> semi-large SOHO-style network, for the reason that the 10 connection 
>> limit
>> is quickly reached.
>>
>> For sockets, there is no limit on the number of inbound connections.
>> Actually, there is a legal limit that's defined in the Windows end-user
>> license agreement, and that number is 10.  Accordingly, if you are using 
>> a
>> product from Microsoft, like IIS, then the limit is imposed by the 
>> product
>> itself (presumably because the product was writtten by Microsoft and MS
>> actually tries to abide by its own EULA).  But if you are using 3rd party
>> products, or writing something on your own, there is no limit, and the OS
>> itself does not try to enforce the EULA limit.  Many users have reported
>> that they successfully manage 1,000's of simultaneous incoming socket
>> connections, even on XP Home systems.
>>
>> There is also no limit on outbound socket connections.  SP2 changed the 
>> TCP
>> stack, and there is now a limit on outbound connections that are
>> *half-open*.  The limit is 10, but half-open connections are not the same
>> thing as established connections.  Half-open refers to a connection that 
>> has
>> not completed TCP's three-way handshake.  The three-way handshake 
>> requires
>> SYN, SYN-ACK and ACK, and in a half-open connection, the SYN has been 
>> sent
>> but the SYN-ACK has not yet been received.  There can only be 10 
>> half-open
>> connections in this state.  Once the three-way handshake has been 
>> completed,
>> then the connection is established, and there is no limit on the number 
>> of
>> established connections.  (The intent of the SP2 change was to slow down 
>> the
>> rate at which new connections are established, but not to limit the 
>> number
>> of actual connections.)
>>
>> With the above in mind, I don't think that your FTP connections are
>> stressing the computer in the right way.  Try sharing files with 10
>> different computers, to see if this produces your E_NOINTERFACE symptoms.
>>
>> Mike
>>
>>
>
>

Regarding the current revision of KB314882:

It states "For Windows XP Professional, the maximum number of other 
computers that are permitted to simultaneously connect over the network is 
ten. This limit includes all transports and resource sharing protocols 
combined". This is very unclear wording to me. The mention of "all 
transports" suggests to me all sockets. Therefore, any kind of connection. 
Is that not what it's getting at?

If you read on, it says "The connection limit refers to the number of 
redirector-based connections and is enforced for any file, print, named 
pipe, or mail slot session". This is clearer, if someone reads this far, but 
I still don't know what redirector-based means when it is not one of the 
aforementioned things. Does RPC count here?

Paul

"Arkady Frenkel"  wrote in message 
news:uG$vVOlVHHA.4796@TK2MSFTNGP05.phx.gbl...
> Additionally : Once 
> http://support.microsoft.com/default.aspx?scid=kb;en-us;314882 looked 
> exactly as
> http://support.microsoft.com/?scid=kb;EN-US;122920 where sockes counted 
> into number of limited sessions which is incorrect ( you can check that by 
> opening IE much more than 10 times :) ) and documentation corrected now as 
> needed ( only SMB and pipe connections counted ). The number of 
> connections in MSFT tests published ( depends of free resources of 
> computer ) was around 50,000 on W2K
> Arkady
>
> "Michael K. O'Neill"  wrote in message 
> news:epAmgreVHHA.1432@TK2MSFTNGP02.phx.gbl...
>>
>> "Paul Baker [MVP, Windows - Networking]" 
>> <paulrichardbaker@community.nospam>
>> wrote in message news:uvuq8vdVHHA.392@TK2MSFTNGP06.phx.gbl...
>>> Excuse me, where I refer to "nbtstat -a", I mean to refer to 
>>> "netstat -a".
>>>
>>> "Paul Baker [MVP, Windows - Networking]"
>> <paulrichardbaker@community.nospam>
>>> wrote in message news:eufPjOdVHHA.1200@TK2MSFTNGP04.phx.gbl...
>>> > "nbtstat -a" shows TCP and  UDP connections
>>>
>>>
>>
>> The "10 connection limit" is widely misunderstood, since that phrase is 
>> used
>> to describe a variety of completely different topics.  To understand the
>> misunderstanding, remember to distinguish between sockets and services.
>> Sockets are what you see from netstat.  Services relate to things like 
>> file
>> sharing and print sharing.  Services might be implemented using sockets, 
>> but
>> with respect to this "10 connection limit" discussion, they are still
>> different.
>>
>> For services, there is a connection limit imposed by the OS: 5 
>> connections
>> for XP Home and 10 for XP Pro.  Thus, you cannot try to share files on a
>> semi-large SOHO-style network, for the reason that the 10 connection 
>> limit
>> is quickly reached.
>>
>> For sockets, there is no limit on the number of inbound connections.
>> Actually, there is a legal limit that's defined in the Windows end-user
>> license agreement, and that number is 10.  Accordingly, if you are using 
>> a
>> product from Microsoft, like IIS, then the limit is imposed by the 
>> product
>> itself (presumably because the product was writtten by Microsoft and MS
>> actually tries to abide by its own EULA).  But if you are using 3rd party
>> products, or writing something on your own, there is no limit, and the OS
>> itself does not try to enforce the EULA limit.  Many users have reported
>> that they successfully manage 1,000's of simultaneous incoming socket
>> connections, even on XP Home systems.
>>
>> There is also no limit on outbound socket connections.  SP2 changed the 
>> TCP
>> stack, and there is now a limit on outbound connections that are
>> *half-open*.  The limit is 10, but half-open connections are not the same
>> thing as established connections.  Half-open refers to a connection that 
>> has
>> not completed TCP's three-way handshake.  The three-way handshake 
>> requires
>> SYN, SYN-ACK and ACK, and in a half-open connection, the SYN has been 
>> sent
>> but the SYN-ACK has not yet been received.  There can only be 10 
>> half-open
>> connections in this state.  Once the three-way handshake has been 
>> completed,
>> then the connection is established, and there is no limit on the number 
>> of
>> established connections.  (The intent of the SP2 change was to slow down 
>> the
>> rate at which new connections are established, but not to limit the 
>> number
>> of actual connections.)
>>
>> With the above in mind, I don't think that your FTP connections are
>> stressing the computer in the right way.  Try sharing files with 10
>> different computers, to see if this produces your E_NOINTERFACE symptoms.
>>
>> Mike
>>
>>
>
>

I wrote a test program that simply opens a shared file and repeatedly reads 
then writes to it. This ensured that a non-idle session remained open.

I ran this test program on 11 different machines with no problem. After 
that, any other machine that tried to connect got an error mentioning a 
connection limit being exceeded. So it was definitely stressed.

Yet it continued to function as a DCOM client and server without issue and 
the E_NOINTERFACE error did *not* occur.

Is this expected behaviour or not? If it is expected, then I don't know what 
to look for to debug this darn E_NOINTERFACE error.

Thanks,

Paul

"Paul Baker [MVP, Windows - Networking]" <paulrichardbaker@community.nospam> 
wrote in message news:e7g9tvoVHHA.3980@TK2MSFTNGP02.phx.gbl...
> Thank to you both.
>
> Is there a way I can reliably identify the number of inbound connections 
> for the purpose of this limit? I am not knowledgeable enough to entirely 
> understand the output of netstat, recognize the port numbers, etc.
>
> What actions are the easiest way to make a connection for file and printer 
> sharing and how do I ensure that I can have 10 inbound connections for 
> file or printer sharing without them timing out? How do I know if they're 
> active? (I am not particularly knowledgeable about this stuff despite my 
> MVP title).
>
> Thanks,
>
> Paul
>
> "Arkady Frenkel"  wrote in message 
> news:uG$vVOlVHHA.4796@TK2MSFTNGP05.phx.gbl...
>> Additionally : Once 
>> http://support.microsoft.com/default.aspx?scid=kb;en-us;314882 looked 
>> exactly as
>> http://support.microsoft.com/?scid=kb;EN-US;122920 where sockes counted 
>> into number of limited sessions which is incorrect ( you can check that 
>> by opening IE much more than 10 times :) ) and documentation corrected 
>> now as needed ( only SMB and pipe connections counted ). The number of 
>> connections in MSFT tests published ( depends of free resources of 
>> computer ) was around 50,000 on W2K
>> Arkady
>>
>> "Michael K. O'Neill"  wrote in message 
>> news:epAmgreVHHA.1432@TK2MSFTNGP02.phx.gbl...
>>>
>>> "Paul Baker [MVP, Windows - Networking]" 
>>> <paulrichardbaker@community.nospam>
>>> wrote in message news:uvuq8vdVHHA.392@TK2MSFTNGP06.phx.gbl...
>>>> Excuse me, where I refer to "nbtstat -a", I mean to refer to 
>>>> "netstat -a".
>>>>
>>>> "Paul Baker [MVP, Windows - Networking]"
>>> <paulrichardbaker@community.nospam>
>>>> wrote in message news:eufPjOdVHHA.1200@TK2MSFTNGP04.phx.gbl...
>>>> > "nbtstat -a" shows TCP and  UDP connections
>>>>
>>>>
>>>
>>> The "10 connection limit" is widely misunderstood, since that phrase is 
>>> used
>>> to describe a variety of completely different topics.  To understand the
>>> misunderstanding, remember to distinguish between sockets and services.
>>> Sockets are what you see from netstat.  Services relate to things like 
>>> file
>>> sharing and print sharing.  Services might be implemented using sockets, 
>>> but
>>> with respect to this "10 connection limit" discussion, they are still
>>> different.
>>>
>>> For services, there is a connection limit imposed by the OS: 5 
>>> connections
>>> for XP Home and 10 for XP Pro.  Thus, you cannot try to share files on a
>>> semi-large SOHO-style network, for the reason that the 10 connection 
>>> limit
>>> is quickly reached.
>>>
>>> For sockets, there is no limit on the number of inbound connections.
>>> Actually, there is a legal limit that's defined in the Windows end-user
>>> license agreement, and that number is 10.  Accordingly, if you are using 
>>> a
>>> product from Microsoft, like IIS, then the limit is imposed by the 
>>> product
>>> itself (presumably because the product was writtten by Microsoft and MS
>>> actually tries to abide by its own EULA).  But if you are using 3rd 
>>> party
>>> products, or writing something on your own, there is no limit, and the 
>>> OS
>>> itself does not try to enforce the EULA limit.  Many users have reported
>>> that they successfully manage 1,000's of simultaneous incoming socket
>>> connections, even on XP Home systems.
>>>
>>> There is also no limit on outbound socket connections.  SP2 changed the 
>>> TCP
>>> stack, and there is now a limit on outbound connections that are
>>> *half-open*.  The limit is 10, but half-open connections are not the 
>>> same
>>> thing as established connections.  Half-open refers to a connection that 
>>> has
>>> not completed TCP's three-way handshake.  The three-way handshake 
>>> requires
>>> SYN, SYN-ACK and ACK, and in a half-open connection, the SYN has been 
>>> sent
>>> but the SYN-ACK has not yet been received.  There can only be 10 
>>> half-open
>>> connections in this state.  Once the three-way handshake has been 
>>> completed,
>>> then the connection is established, and there is no limit on the number 
>>> of
>>> established connections.  (The intent of the SP2 change was to slow down 
>>> the
>>> rate at which new connections are established, but not to limit the 
>>> number
>>> of actual connections.)
>>>
>>> With the above in mind, I don't think that your FTP connections are
>>> stressing the computer in the right way.  Try sharing files with 10
>>> different computers, to see if this produces your E_NOINTERFACE 
>>> symptoms.
>>>
>>> Mike
>>>
>>>
>>
>>
>
>

[This is better asked on microsoft.public.win32.programmer.networks. This 
group is almost dead while programmer.networks has a few MS RPC people 
around. Follow-up set accordingly]

Paul Baker [MVP, Windows - Networking] wrote:
> It just happened again.
>
> This is the output of "rpcping -s ncoantfs -v 3", where "ncoantfs" is
> the name of the Windows XP Professional machine. I ran it on of the
> Windows Server 2003 Service Pack 1 servers, named "ncoalink".
>
> "RPCPing v2.12. Copyright (C) Microsoft Corporation, 2002
> OS Version is: 5.2
>
> Exception 5 (0x00000005)"

[...]

> What does it all mean? :)

Nobody there, most likely ;-) You can see the same error when pinging an XP 
box with no RPC servers on it.
It could also be a genuine "access denied" authentication error but I doubt 
it in your case.

Is the XP machine you use a clean one? Do you have any 3rd party "security" 
software (firewalls, anti-spyware etc.) on it?

-- 
Eugene
http://www.gershnik.com

It just happened again.

This is the output of "rpcping -s ncoantfs -v 3", where "ncoantfs" is the 
name of the Windows XP Professional machine. I ran it on of the Windows 
Server 2003 Service Pack 1 servers, named "ncoalink".

"RPCPing v2.12. Copyright (C) Microsoft Corporation, 2002
OS Version is: 5.2

Exception 5 (0x00000005)"

At the same time:
- There was only four sessions according to "net session", all for printer 
sharing.
- I could open the remote Printers and Faxes folder in Windows Explorer for 
"ncoantfs" on "ncoalink" and use it to print a test page without issue.
- I could open Computer Management on "ncoalink" and use it to connect to 
"ncoantfs" without issue.


What does it all mean? :)

Paul

"Paul Baker [MVP, Windows - Networking]" <paulrichardbaker@community.nospam> 
wrote in message news:uLzSnHtVHHA.5008@TK2MSFTNGP05.phx.gbl...
>I wrote a test program that simply opens a shared file and repeatedly reads 
>then writes to it. This ensured that a non-idle session remained open.
>
> I ran this test program on 11 different machines with no problem. After 
> that, any other machine that tried to connect got an error mentioning a 
> connection limit being exceeded. So it was definitely stressed.
>
> Yet it continued to function as a DCOM client and server without issue and 
> the E_NOINTERFACE error did *not* occur.
>
> Is this expected behaviour or not? If it is expected, then I don't know 
> what to look for to debug this darn E_NOINTERFACE error.
>
> Thanks,
>
> Paul
>
> "Paul Baker [MVP, Windows - Networking]" 
> <paulrichardbaker@community.nospam> wrote in message 
> news:e7g9tvoVHHA.3980@TK2MSFTNGP02.phx.gbl...
>> Thank to you both.
>>
>> Is there a way I can reliably identify the number of inbound connections 
>> for the purpose of this limit? I am not knowledgeable enough to entirely 
>> understand the output of netstat, recognize the port numbers, etc.
>>
>> What actions are the easiest way to make a connection for file and 
>> printer sharing and how do I ensure that I can have 10 inbound 
>> connections for file or printer sharing without them timing out? How do I 
>> know if they're active? (I am not particularly knowledgeable about this 
>> stuff despite my MVP title).
>>
>> Thanks,
>>
>> Paul
>>
>> "Arkady Frenkel"  wrote in message 
>> news:uG$vVOlVHHA.4796@TK2MSFTNGP05.phx.gbl...
>>> Additionally : Once 
>>> http://support.microsoft.com/default.aspx?scid=kb;en-us;314882 looked 
>>> exactly as
>>> http://support.microsoft.com/?scid=kb;EN-US;122920 where sockes counted 
>>> into number of limited sessions which is incorrect ( you can check that 
>>> by opening IE much more than 10 times :) ) and documentation corrected 
>>> now as needed ( only SMB and pipe connections counted ). The number of 
>>> connections in MSFT tests published ( depends of free resources of 
>>> computer ) was around 50,000 on W2K
>>> Arkady
>>>
>>> "Michael K. O'Neill"  wrote in message 
>>> news:epAmgreVHHA.1432@TK2MSFTNGP02.phx.gbl...
>>>>
>>>> "Paul Baker [MVP, Windows - Networking]" 
>>>> <paulrichardbaker@community.nospam>
>>>> wrote in message news:uvuq8vdVHHA.392@TK2MSFTNGP06.phx.gbl...
>>>>> Excuse me, where I refer to "nbtstat -a", I mean to refer to 
>>>>> "netstat -a".
>>>>>
>>>>> "Paul Baker [MVP, Windows - Networking]"
>>>> <paulrichardbaker@community.nospam>
>>>>> wrote in message news:eufPjOdVHHA.1200@TK2MSFTNGP04.phx.gbl...
>>>>> > "nbtstat -a" shows TCP and  UDP connections
>>>>>
>>>>>
>>>>
>>>> The "10 connection limit" is widely misunderstood, since that phrase is 
>>>> used
>>>> to describe a variety of completely different topics.  To understand 
>>>> the
>>>> misunderstanding, remember to distinguish between sockets and services.
>>>> Sockets are what you see from netstat.  Services relate to things like 
>>>> file
>>>> sharing and print sharing.  Services might be implemented using 
>>>> sockets, but
>>>> with respect to this "10 connection limit" discussion, they are still
>>>> different.
>>>>
>>>> For services, there is a connection limit imposed by the OS: 5 
>>>> connections
>>>> for XP Home and 10 for XP Pro.  Thus, you cannot try to share files on 
>>>> a
>>>> semi-large SOHO-style network, for the reason that the 10 connection 
>>>> limit
>>>> is quickly reached.
>>>>
>>>> For sockets, there is no limit on the number of inbound connections.
>>>> Actually, there is a legal limit that's defined in the Windows end-user
>>>> license agreement, and that number is 10.  Accordingly, if you are 
>>>> using a
>>>> product from Microsoft, like IIS, then the limit is imposed by the 
>>>> product
>>>> itself (presumably because the product was writtten by Microsoft and MS
>>>> actually tries to abide by its own EULA).  But if you are using 3rd 
>>>> party
>>>> products, or writing something on your own, there is no limit, and the 
>>>> OS
>>>> itself does not try to enforce the EULA limit.  Many users have 
>>>> reported
>>>> that they successfully manage 1,000's of simultaneous incoming socket
>>>> connections, even on XP Home systems.
>>>>
>>>> There is also no limit on outbound socket connections.  SP2 changed the 
>>>> TCP
>>>> stack, and there is now a limit on outbound connections that are
>>>> *half-open*.  The limit is 10, but half-open connections are not the 
>>>> same
>>>> thing as established connections.  Half-open refers to a connection 
>>>> that has
>>>> not completed TCP's three-way handshake.  The three-way handshake 
>>>> requires
>>>> SYN, SYN-ACK and ACK, and in a half-open connection, the SYN has been 
>>>> sent
>>>> but the SYN-ACK has not yet been received.  There can only be 10 
>>>> half-open
>>>> connections in this state.  Once the three-way handshake has been 
>>>> completed,
>>>> then the connection is established, and there is no limit on the number 
>>>> of
>>>> established connections.  (The intent of the SP2 change was to slow 
>>>> down the
>>>> rate at which new connections are established, but not to limit the 
>>>> number
>>>> of actual connections.)
>>>>
>>>> With the above in mind, I don't think that your FTP connections are
>>>> stressing the computer in the right way.  Try sharing files with 10
>>>> different computers, to see if this produces your E_NOINTERFACE 
>>>> symptoms.
>>>>
>>>> Mike
>>>>
>>>>
>>>
>>>
>>
>>
>
>

As I wrote that number counted only SMB sessions and other different than 
winsock IPC sessions( IMHO RPC included too )
Arkady


"Paul Baker [MVP, Windows - Networking]" <paulrichardbaker@community.nospam> 
wrote in message news:%23NFWwyoVHHA.4796@TK2MSFTNGP05.phx.gbl...
> Regarding the current revision of KB314882:
>
> It states "For Windows XP Professional, the maximum number of other 
> computers that are permitted to simultaneously connect over the network is 
> ten. This limit includes all transports and resource sharing protocols 
> combined". This is very unclear wording to me. The mention of "all 
> transports" suggests to me all sockets. Therefore, any kind of connection. 
> Is that not what it's getting at?
>
> If you read on, it says "The connection limit refers to the number of 
> redirector-based connections and is enforced for any file, print, named 
> pipe, or mail slot session". This is clearer, if someone reads this far, 
> but I still don't know what redirector-based means when it is not one of 
> the aforementioned things. Does RPC count here?
>
> Paul
>
> "Arkady Frenkel"  wrote in message 
> news:uG$vVOlVHHA.4796@TK2MSFTNGP05.phx.gbl...
>> Additionally : Once 
>> http://support.microsoft.com/default.aspx?scid=kb;en-us;314882 looked 
>> exactly as
>> http://support.microsoft.com/?scid=kb;EN-US;122920 where sockes counted 
>> into number of limited sessions which is incorrect ( you can check that 
>> by opening IE much more than 10 times :) ) and documentation corrected 
>> now as needed ( only SMB and pipe connections counted ). The number of 
>> connections in MSFT tests published ( depends of free resources of 
>> computer ) was around 50,000 on W2K
>> Arkady
>>
>> "Michael K. O'Neill"  wrote in message 
>> news:epAmgreVHHA.1432@TK2MSFTNGP02.phx.gbl...
>>>
>>> "Paul Baker [MVP, Windows - Networking]" 
>>> <paulrichardbaker@community.nospam>
>>> wrote in message news:uvuq8vdVHHA.392@TK2MSFTNGP06.phx.gbl...
>>>> Excuse me, where I refer to "nbtstat -a", I mean to refer to 
>>>> "netstat -a".
>>>>
>>>> "Paul Baker [MVP, Windows - Networking]"
>>> <paulrichardbaker@community.nospam>
>>>> wrote in message news:eufPjOdVHHA.1200@TK2MSFTNGP04.phx.gbl...
>>>> > "nbtstat -a" shows TCP and  UDP connections
>>>>
>>>>
>>>
>>> The "10 connection limit" is widely misunderstood, since that phrase is 
>>> used
>>> to describe a variety of completely different topics.  To understand the
>>> misunderstanding, remember to distinguish between sockets and services.
>>> Sockets are what you see from netstat.  Services relate to things like 
>>> file
>>> sharing and print sharing.  Services might be implemented using sockets, 
>>> but
>>> with respect to this "10 connection limit" discussion, they are still
>>> different.
>>>
>>> For services, there is a connection limit imposed by the OS: 5 
>>> connections
>>> for XP Home and 10 for XP Pro.  Thus, you cannot try to share files on a
>>> semi-large SOHO-style network, for the reason that the 10 connection 
>>> limit
>>> is quickly reached.
>>>
>>> For sockets, there is no limit on the number of inbound connections.
>>> Actually, there is a legal limit that's defined in the Windows end-user
>>> license agreement, and that number is 10.  Accordingly, if you are using 
>>> a
>>> product from Microsoft, like IIS, then the limit is imposed by the 
>>> product
>>> itself (presumably because the product was writtten by Microsoft and MS
>>> actually tries to abide by its own EULA).  But if you are using 3rd 
>>> party
>>> products, or writing something on your own, there is no limit, and the 
>>> OS
>>> itself does not try to enforce the EULA limit.  Many users have reported
>>> that they successfully manage 1,000's of simultaneous incoming socket
>>> connections, even on XP Home systems.
>>>
>>> There is also no limit on outbound socket connections.  SP2 changed the 
>>> TCP
>>> stack, and there is now a limit on outbound connections that are
>>> *half-open*.  The limit is 10, but half-open connections are not the 
>>> same
>>> thing as established connections.  Half-open refers to a connection that 
>>> has
>>> not completed TCP's three-way handshake.  The three-way handshake 
>>> requires
>>> SYN, SYN-ACK and ACK, and in a half-open connection, the SYN has been 
>>> sent
>>> but the SYN-ACK has not yet been received.  There can only be 10 
>>> half-open
>>> connections in this state.  Once the three-way handshake has been 
>>> completed,
>>> then the connection is established, and there is no limit on the number 
>>> of
>>> established connections.  (The intent of the SP2 change was to slow down 
>>> the
>>> rate at which new connections are established, but not to limit the 
>>> number
>>> of actual connections.)
>>>
>>> With the above in mind, I don't think that your FTP connections are
>>> stressing the computer in the right way.  Try sharing files with 10
>>> different computers, to see if this produces your E_NOINTERFACE 
>>> symptoms.
>>>
>>> Mike
>>>
>>>
>>
>>
>
>

Just check with WinObject from sysinternals what you have in Sessions 
( ->0->DosDevices ) SMB drivers listed there you don't see in "net sessions" 
but they have to be counted too
Arkady
P.S. Eugene already include the answer in networks NG too, but you can ask 
there all your question for gurus to see all the picture. OTOH DCOM at the 
end use TCP ( UDP at the beginning ) so that should be not counted as 10 
limit


"Paul Baker [MVP, Windows - Networking]" <paulrichardbaker@community.nospam> 
wrote in message news:uu6eup5VHHA.4764@TK2MSFTNGP05.phx.gbl...
> It just happened again.
>
> This is the output of "rpcping -s ncoantfs -v 3", where "ncoantfs" is the 
> name of the Windows XP Professional machine. I ran it on of the Windows 
> Server 2003 Service Pack 1 servers, named "ncoalink".
>
> "RPCPing v2.12. Copyright (C) Microsoft Corporation, 2002
> OS Version is: 5.2
>
> Exception 5 (0x00000005)"
>
> At the same time:
> - There was only four sessions according to "net session", all for printer 
> sharing.
> - I could open the remote Printers and Faxes folder in Windows Explorer 
> for "ncoantfs" on "ncoalink" and use it to print a test page without 
> issue.
> - I could open Computer Management on "ncoalink" and use it to connect to 
> "ncoantfs" without issue.
>
>
> What does it all mean? :)
>
> Paul
>
> "Paul Baker [MVP, Windows - Networking]" 
> <paulrichardbaker@community.nospam> wrote in message 
> news:uLzSnHtVHHA.5008@TK2MSFTNGP05.phx.gbl...
>>I wrote a test program that simply opens a shared file and repeatedly 
>>reads then writes to it. This ensured that a non-idle session remained 
>>open.
>>
>> I ran this test program on 11 different machines with no problem. After 
>> that, any other machine that tried to connect got an error mentioning a 
>> connection limit being exceeded. So it was definitely stressed.
>>
>> Yet it continued to function as a DCOM client and server without issue 
>> and the E_NOINTERFACE error did *not* occur.
>>
>> Is this expected behaviour or not? If it is expected, then I don't know 
>> what to look for to debug this darn E_NOINTERFACE error.
>>
>> Thanks,
>>
>> Paul
>>
>> "Paul Baker [MVP, Windows - Networking]" 
>> <paulrichardbaker@community.nospam> wrote in message 
>> news:e7g9tvoVHHA.3980@TK2MSFTNGP02.phx.gbl...
>>> Thank to you both.
>>>
>>> Is there a way I can reliably identify the number of inbound connections 
>>> for the purpose of this limit? I am not knowledgeable enough to entirely 
>>> understand the output of netstat, recognize the port numbers, etc.
>>>
>>> What actions are the easiest way to make a connection for file and 
>>> printer sharing and how do I ensure that I can have 10 inbound 
>>> connections for file or printer sharing without them timing out? How do 
>>> I know if they're active? (I am not particularly knowledgeable about 
>>> this stuff despite my MVP title).
>>>
>>> Thanks,
>>>
>>> Paul
>>>
>>> "Arkady Frenkel"  wrote in message 
>>> news:uG$vVOlVHHA.4796@TK2MSFTNGP05.phx.gbl...
>>>> Additionally : Once 
>>>> http://support.microsoft.com/default.aspx?scid=kb;en-us;314882 looked 
>>>> exactly as
>>>> http://support.microsoft.com/?scid=kb;EN-US;122920 where sockes counted 
>>>> into number of limited sessions which is incorrect ( you can check that 
>>>> by opening IE much more than 10 times :) ) and documentation corrected 
>>>> now as needed ( only SMB and pipe connections counted ). The number of 
>>>> connections in MSFT tests published ( depends of free resources of 
>>>> computer ) was around 50,000 on W2K
>>>> Arkady
>>>>
>>>> "Michael K. O'Neill"  wrote in 
>>>> message news:epAmgreVHHA.1432@TK2MSFTNGP02.phx.gbl...
>>>>>
>>>>> "Paul Baker [MVP, Windows - Networking]" 
>>>>> <paulrichardbaker@community.nospam>
>>>>> wrote in message news:uvuq8vdVHHA.392@TK2MSFTNGP06.phx.gbl...
>>>>>> Excuse me, where I refer to "nbtstat -a", I mean to refer to 
>>>>>> "netstat -a".
>>>>>>
>>>>>> "Paul Baker [MVP, Windows - Networking]"
>>>>> <paulrichardbaker@community.nospam>
>>>>>> wrote in message news:eufPjOdVHHA.1200@TK2MSFTNGP04.phx.gbl...
>>>>>> > "nbtstat -a" shows TCP and  UDP connections
>>>>>>
>>>>>>
>>>>>
>>>>> The "10 connection limit" is widely misunderstood, since that phrase 
>>>>> is used
>>>>> to describe a variety of completely different topics.  To understand 
>>>>> the
>>>>> misunderstanding, remember to distinguish between sockets and 
>>>>> services.
>>>>> Sockets are what you see from netstat.  Services relate to things like 
>>>>> file
>>>>> sharing and print sharing.  Services might be implemented using 
>>>>> sockets, but
>>>>> with respect to this "10 connection limit" discussion, they are still
>>>>> different.
>>>>>
>>>>> For services, there is a connection limit imposed by the OS: 5 
>>>>> connections
>>>>> for XP Home and 10 for XP Pro.  Thus, you cannot try to share files on 
>>>>> a
>>>>> semi-large SOHO-style network, for the reason that the 10 connection 
>>>>> limit
>>>>> is quickly reached.
>>>>>
>>>>> For sockets, there is no limit on the number of inbound connections.
>>>>> Actually, there is a legal limit that's defined in the Windows 
>>>>> end-user
>>>>> license agreement, and that number is 10.  Accordingly, if you are 
>>>>> using a
>>>>> product from Microsoft, like IIS, then the limit is imposed by the 
>>>>> product
>>>>> itself (presumably because the product was writtten by Microsoft and 
>>>>> MS
>>>>> actually tries to abide by its own EULA).  But if you are using 3rd 
>>>>> party
>>>>> products, or writing something on your own, there is no limit, and the 
>>>>> OS
>>>>> itself does not try to enforce the EULA limit.  Many users have 
>>>>> reported
>>>>> that they successfully manage 1,000's of simultaneous incoming socket
>>>>> connections, even on XP Home systems.
>>>>>
>>>>> There is also no limit on outbound socket connections.  SP2 changed 
>>>>> the TCP
>>>>> stack, and there is now a limit on outbound connections that are
>>>>> *half-open*.  The limit is 10, but half-open connections are not the 
>>>>> same
>>>>> thing as established connections.  Half-open refers to a connection 
>>>>> that has
>>>>> not completed TCP's three-way handshake.  The three-way handshake 
>>>>> requires
>>>>> SYN, SYN-ACK and ACK, and in a half-open connection, the SYN has been 
>>>>> sent
>>>>> but the SYN-ACK has not yet been received.  There can only be 10 
>>>>> half-open
>>>>> connections in this state.  Once the three-way handshake has been 
>>>>> completed,
>>>>> then the connection is established, and there is no limit on the 
>>>>> number of
>>>>> established connections.  (The intent of the SP2 change was to slow 
>>>>> down the
>>>>> rate at which new connections are established, but not to limit the 
>>>>> number
>>>>> of actual connections.)
>>>>>
>>>>> With the above in mind, I don't think that your FTP connections are
>>>>> stressing the computer in the right way.  Try sharing files with 10
>>>>> different computers, to see if this produces your E_NOINTERFACE 
>>>>> symptoms.
>>>>>
>>>>> Mike
>>>>>
>>>>>
>>>>
>>>>
>>>
>>>
>>
>>
>
>

Yes, there are third party software tools potentially involved:

Symantec Anti-Virus Enterprise Edition
Spysweeper.

There is also a hardware-based firewall protecting our LAN, I am told that
this does not interfere with internal traffic.

Paul

"Eugene Gershnik"  wrote in message 
news:umwj5$LWHHA.5060@TK2MSFTNGP06.phx.gbl...
> [This is better asked on microsoft.public.win32.programmer.networks. This 
> group is almost dead while programmer.networks has a few MS RPC people 
> around. Follow-up set accordingly]
>
> Paul Baker [MVP, Windows - Networking] wrote:
>> It just happened again.
>>
>> This is the output of "rpcping -s ncoantfs -v 3", where "ncoantfs" is
>> the name of the Windows XP Professional machine. I ran it on of the
>> Windows Server 2003 Service Pack 1 servers, named "ncoalink".
>>
>> "RPCPing v2.12. Copyright (C) Microsoft Corporation, 2002
>> OS Version is: 5.2
>>
>> Exception 5 (0x00000005)"
>
> [...]
>
>> What does it all mean? :)
>
> Nobody there, most likely ;-) You can see the same error when pinging an 
> XP box with no RPC servers on it.
> It could also be a genuine "access denied" authentication error but I 
> doubt it in your case.
>
> Is the XP machine you use a clean one? Do you have any 3rd party 
> "security" software (firewalls, anti-spyware etc.) on it?
>
> -- 
> Eugene
> http://www.gershnik.com
>
>

Thanks Eugene and Arkady,

I wrote a test program that opens a shared file on my Windows XP development
machine, which had a similar setup, and repeatedly reads from then write to
it every ten seconds. I had as many people as possible in the building run
it. At one point, I had 11 sessions according to "net session", none of
which were idle. There was no connection of any kind to the Windows Server
2003 Service Pack 1 server I was testing DCOM with at that point, according
to "netstat -a". So, regardless of how the 10 connection limit is counted, I
would say I exceeded it. Several people attempted to connect beyond that,
and all received a error of some sort, mostly ERROR_REQ_NOT_ACCEP. Yet, the
DCOM server was able to connect to the Windows Sever 2003 Service Pack 1
server and continued to function as normal! This would suggest to me that
the 10 connection limit is not the cause.

You say "nobody is there". Well, the RPC server *is* there, because the
print server and Computer Management still work (for example). But it's not
taking care of the DCOM stuff for some reason. Getting it to listen is like
trying to get my kids to clean up their room. I wish I could restart the RPC
server just to see if that resolves it, but such actions are disabled and so
I must reboot. Terminating the services.exe process hosting the RPC server,
which many other services rely upon, does not achieve anything good. For
example, it seems to break the Running Object Table.

I don't have much to say about your comments on SMB sessions, because
although I have herad of it, I don't know much about it. I am using
FindFirstChangeNotification on one remote folder. Is that relevant?

I will also tell my story again on
"microsoft.public.win32.programmer.networks". See you there? :)

Paul

"Eugene Gershnik"  wrote in message
news:umwj5$LWHHA.5060@TK2MSFTNGP06.phx.gbl...
> [This is better asked on microsoft.public.win32.programmer.networks. This 
> group is almost dead while programmer.networks has a few MS RPC people 
> around. Follow-up set accordingly]
>
> Paul Baker [MVP, Windows - Networking] wrote:
>> It just happened again.
>>
>> This is the output of "rpcping -s ncoantfs -v 3", where "ncoantfs" is
>> the name of the Windows XP Professional machine. I ran it on of the
>> Windows Server 2003 Service Pack 1 servers, named "ncoalink".
>>
>> "RPCPing v2.12. Copyright (C) Microsoft Corporation, 2002
>> OS Version is: 5.2
>>
>> Exception 5 (0x00000005)"
>
> [...]
>
>> What does it all mean? :)
>
> Nobody there, most likely ;-) You can see the same error when pinging an 
> XP box with no RPC servers on it.
> It could also be a genuine "access denied" authentication error but I 
> doubt it in your case.
>
> Is the XP machine you use a clean one? Do you have any 3rd party 
> "security" software (firewalls, anti-spyware etc.) on it?
>
> -- 
> Eugene
> http://www.gershnik.com
>
>

Thanks Eugene and Arkady,

I wrote a test program that opens a shared file on my Windows XP development 
machine, which had a similar setup, and repeatedly reads from then write to 
it every ten seconds. I had as many people as possible in the building run 
it. At one point, I had 11 sessions according to "net session", none of 
which were idle. There was no connection of any kind to the Windows Server 
2003 Service Pack 1 server I was testing DCOM with at that point, according 
to "netstat -a". So, regardless of how the 10 connection limit is counted, I 
would say I exceeded it. Several people attempted to connect beyond that, 
and all received a error of some sort, mostly ERROR_REQ_NOT_ACCEP. Yet, the 
DCOM server was able to connect to the Windows Sever 2003 Service Pack 1 
server and continued to function as normal! This would suggest to me that 
the 10 connection limit is not the cause.

You say "nobody is there". Well, the RPC server *is* there, because the 
print server and Computer Management still work (for example). But it's not 
taking care of the DCOM stuff for some reason. Getting it to listen is like 
trying to get my kids to clean up their room. I wish I could restart the RPC 
server just to see if that resolves it, but such actions are disabled and so 
I must reboot. Terminating the services.exe process hosting the RPC server, 
which many other services rely upon, does not achieve anything good. For 
example, it seems to break the Running Object Table.

I don't have much to say about your comments on SMB sessions, because 
although I have herad of it, I don't know much about it. I am using 
FindFirstChangeNotification on one remote folder. Is that relevant?

I will also tell my story again on 
"microsoft.public.win32.programmer.networks". See you there? :)

Paul

"Eugene Gershnik"  wrote in message 
news:umwj5$LWHHA.5060@TK2MSFTNGP06.phx.gbl...
> [This is better asked on microsoft.public.win32.programmer.networks. This 
> group is almost dead while programmer.networks has a few MS RPC people 
> around. Follow-up set accordingly]
>
> Paul Baker [MVP, Windows - Networking] wrote:
>> It just happened again.
>>
>> This is the output of "rpcping -s ncoantfs -v 3", where "ncoantfs" is
>> the name of the Windows XP Professional machine. I ran it on of the
>> Windows Server 2003 Service Pack 1 servers, named "ncoalink".
>>
>> "RPCPing v2.12. Copyright (C) Microsoft Corporation, 2002
>> OS Version is: 5.2
>>
>> Exception 5 (0x00000005)"
>
> [...]
>
>> What does it all mean? :)
>
> Nobody there, most likely ;-) You can see the same error when pinging an 
> XP box with no RPC servers on it.
> It could also be a genuine "access denied" authentication error but I 
> doubt it in your case.
>
> Is the XP machine you use a clean one? Do you have any 3rd party 
> "security" software (firewalls, anti-spyware etc.) on it?
>
> -- 
> Eugene
> http://www.gershnik.com
>
>

Yes, there are third party software tools potentially involved:

Symantec Anti-Virus Enterprise Edition
Spysweeper.

There is also a hardware-based firewall protecting our LAN, I am told that 
this does not interfere with internal traffic.

Paul

"Eugene Gershnik"  wrote in message 
news:umwj5$LWHHA.5060@TK2MSFTNGP06.phx.gbl...
> [This is better asked on microsoft.public.win32.programmer.networks. This 
> group is almost dead while programmer.networks has a few MS RPC people 
> around. Follow-up set accordingly]
>
> Paul Baker [MVP, Windows - Networking] wrote:
>> It just happened again.
>>
>> This is the output of "rpcping -s ncoantfs -v 3", where "ncoantfs" is
>> the name of the Windows XP Professional machine. I ran it on of the
>> Windows Server 2003 Service Pack 1 servers, named "ncoalink".
>>
>> "RPCPing v2.12. Copyright (C) Microsoft Corporation, 2002
>> OS Version is: 5.2
>>
>> Exception 5 (0x00000005)"
>
> [...]
>
>> What does it all mean? :)
>
> Nobody there, most likely ;-) You can see the same error when pinging an 
> XP box with no RPC servers on it.
> It could also be a genuine "access denied" authentication error but I 
> doubt it in your case.
>
> Is the XP machine you use a clean one? Do you have any 3rd party 
> "security" software (firewalls, anti-spyware etc.) on it?
>
> -- 
> Eugene
> http://www.gershnik.com
>
>

Paul Baker [MVP, Windows - Networking] wrote:
> Yes, there are third party software tools potentially involved:
>
> Symantec Anti-Virus Enterprise Edition
> Spysweeper.

Completely uninstall both then try again ;-) Don't just disable but uninstal 
since their drivers continue to work even when "disabled". All "security" 
tools may (and in Symantec case do) introduce hard to reproduce bugs into 
the system.


-- 
Eugene
http://www.gershnik.com

Paul Baker [MVP, Windows - Networking] wrote:
> You say "nobody is there". Well, the RPC server *is* there, because
> the print server and Computer Management still work (for example).

AFAIK they have nothing to do with RPC but just use normal redirector.

> But it's not taking care of the DCOM stuff for some reason.

Which probably means that the RPC (as opposed to the general SMB) server is 
down.

Try your test with "security" software disabled and let's see what happens.

-- 
Eugene
http://www.gershnik.com