Re: SQL 2000 drops connection, DDOS attack?

I forgot to ask, but did you reboot after applying the KB 899599 change?

The nebulous 'general network error' basically means that something broke in
the network layer. This could be caused by hardware, bad NIC driver, TDS
problem, etc.. If you have a quality network infrastructure and are
up-to-date Windows Update, the only thing I can suggest (asside from a
support call) is to try to workaround the issue.

One thing you might try is specifying an alternate protocol in your
connection string (e.g. Network Library=DBNMPNTW).

We open 1000's one after the other. In psudo code would be similar to

open recordset of customers
for each customer, open recordset of invoices
for each invoice, open recordset of payments
close payments
close invoice
close customers

all on the same connection.

Based on your pseudo-code, you will need 3 separate connections (unless you
are using client-side recordsets) because it is not possible to have
multiple active queries on a single connection in SQL 2000. Note that ADO
will silently open a new connection behind the scenes if the current one is
busy. You can run a profiler trace to verify this is the case with your
application.

At a glance, it seems you could issue a single query to retrieve the
necessary data. Not only might this avert the network problem due to the
reduced network stress, it is likely that you would improve query
performance by an order or magnitude. For example:

SELECT
CustomerData,
InvoiceData,
PaymentData
FROM Customers
JOIN Invoices ON Customers.CustomerId = Invoices.CustomerId
JOIN Payments ON Payments.InvoiceId = Invoices.InvoiceId
WHERE InvoiceDate >= '20060101' AND InvoiceDate < '20060201'

--
Hope this helps.

Dan Guzman
SQL Server MVP

"Chris" <Chris@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
news:1B20F59F-7B09-458B-9C1B-5B4FEEF85E8A@xxxxxxxxxxxxxxxx
It is as if the database connection is lost yes, or network died.

We open 1000's one after the other. In psudo code would be similar to

open recordset of customers
for each customer, open recordset of invoices
for each invoice, open recordset of payments
close payments
close invoice
close customers

all on the same connection.

It works ok on the server - and can work ok on a client. If running
through
say 1000 customers may fail several times, but continuing on the same line
where the error happened is possible if you wait a few seconds.


"Dan Guzman" wrote:

[DBNETLIB][ConnectionOpen (Connect()).]SQL Server does not exist or
access
denied.

This looks like the kid of error you'll get during a connection attempt
when
there is no network connectivity to the SQL box or the SQL Server
instance
isn't running or name resolution fails. Does this follow the 'general
network' error you mentioned previously?

What exactly do you mean when you say that you are 'opening multiple
recordsets, literally 1000s at a time'? Is it that you execute a series
of
queries in a loop on the same connection? In that case, be sure that you
close the recordset before executing another query. Some data access
APIs
will silently open another database connection if the current connection
is
busy. Perhaps some pseudo or actual code will help identify where the
problem may lie.


--
Hope this helps.

Dan Guzman
SQL Server MVP

"Chris" <Chris@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
news:A936F49C-7381-4B14-844F-58933DE34A64@xxxxxxxxxxxxxxxx
Dan,

Run-time error '-2147467259 (80004005)':

[DBNETLIB][ConnectionOpen (Connect()).]SQL Server does not exist or
access
denied.

Hope this helps. Thanks

"Dan Guzman" wrote:

What's the exact error you get from the application? If it's a
'general
network error', you might try using a different protocol. This can be
done
using the Client Network utility or specified in the connection
string.

--
Hope this helps.

Dan Guzman
SQL Server MVP

"Chris" <Chris@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
news:3792EA5E-A646-400F-BE69-3B633807297E@xxxxxxxxxxxxxxxx
Dan,

I have tried this one before and it still doesn't get around the
problem:
1. Click Start, click Run, type regedit, and then click OK.
2. Locate and then click the following registry key:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters
3. On the Edit menu, point to New, and then click DWORD Value.
4. Type SynAttackProtect, and then press ENTER.
5. On the Edit menu, click Modify.
6. In the Value data box, type 00000000. Click OK.
7. Quit Registry Editor.

Any other ideas please?? I would have thought this would have sorted
it,
but
no. Please help. Thanks

"Dan Guzman" wrote:

Check out http://support.microsoft.com/kb/899599/en-us

--
Hope this helps.

Dan Guzman
SQL Server MVP

"Chris" <Chris@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
news:A0620D88-A311-4346-A903-9556A66C40A8@xxxxxxxxxxxxxxxx
This is relating to SQL slammer question I posted.
We open 1 connection to SQL and we're
opening multiple recordsets, literally 1000s at a time. If you
run
it
on
the
server that is running SQL 2000 it's fine...but do this from a
client
PC
then
you get a general network error. It's dropping the initial SQL
connection
halfway through running a recordset lookup and causes an
error...as
the
connection has been dropped. We can put a 30 second delay in
there
and
this
gets around the problem, while it restablishes the connection,
but
this
is
not practical. There must be something that can be done to tell
SQL
2000
or
server 2003 sp1 to leave the connection alone when it's
connected??
Any
ideas
anyone? Thanks











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