Hi John,

I hate to give you such imprecise hint, but I've encountered a similar
problem at one of our customers' and it turned out a network switch (you
know, one of the "smart" ones ;) ) kept dropping connections when there
was no traffic on the wire for some time.
Unfortunately I can't find the exact model or even vendor of the switch.
However, there's a simple test to confirm the switch is the cause: try
to leave your application for a couple of minutes (in our case it was
about a quarter of an hour) without any activity and check if the
connection was closed (e.g. by doing something in the client app that
requires the DB connection). Reconfiguration of the switch solved our
problem.
To be honest, I've also heard client-side firewalls cause problems from
time to time, just like Mark Rotteveel wrote. Never experienced it, though.

regards
Tomasz

On 2011-10-19 08:06, gwc8182 wrote:
> Hi everyone,
>
> I have encountered a weird network problem and have no idea what might be the cause of it.
>
> Background info: Using Firebird 2.0.5
> Program is written on Delphi with BDE.
> Server is Windows 7 Ultimate
> Clients are running mixed of Windows 7 Starter, Home Premium, WinXP, Vista Home Premium.
>
> Client connection path to the database is using TCP/IP
>
>
> Situation: Client's program frequently shows
> Error writing data to the connection
> An existing connection was forcibly closed by the remote host
>
> Client stated it happened after using the program for some time.
> As testing, I tried saving couple of big transaction on the client computer and will encountered the same error. Note: Processing time for the transaction takes less then 3 mins.
>
> Initially thought might be related to memory but hit the same problem with a computer with 2 GB memory. Tried adjusting memory usage in Firebird.conf file but makes no different. Firebird.conf was then restore back to original to continue testing for other possibility.
>
> Testing on network so far shows it is stable.
> Perform test by pinging the server and then transferring file to the server while the program is running. Will get the same error above but ping and file transfer continue without hiccup.
> Perform another test by having two program open. Only the program running the test above will crashed with error and the second program can continue being used without any problem.
>
>
> Server Firebird's log file only recorded 10054 error.
> Tried running both SuperServer and Classic mode and
> tried Firebird 2.5.1 as well but no go.
>
> Also suspected something is not right with the program but running the same test at my own office with lower end computer and much heavier transaction will not have any problem. I pretty much given up and not sure what so unique about this client network that keep getting this error.
>
> Thanks and regards,
> John
>
>
>


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__--==============================--__
__--== Tomasz Tyrakowski ==--__
__--== SOL-SYSTEM ==--__
__--== http://www.sol-system.pl ==--__
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