Incomplete download in IIS6

[Samurai]

I have this ASP application that delivers binary files (by calling C++ COM
object) to a C++ client application. On the server side I read from a file
and write it using Response.BinaryWrite function. On the client side I read
using the MFC CHttpFile::Read() function.

This code has been working for 5 years on Win2000/IIS5. Recently we moved
the ASP application as is into Windows 2003/IIS6. Since then we are seeing
that some large size files are delivered incomplete. There is no error on
both side. I have run the server side C++ COM object via debugger and found
no error, it writes the entire 5MB file without error. I have also run the
client side C++ application via debugger, and it receives 1.6MB and then
terminates without any error.

Whatever happened to rest of the file? I can reproduce this error everytime
for a given file. However, this doesn't happen for most of the files.

Please shed some light here...

 

[Paul]

Do you have URLScan configured on your server? I think this can limit the
download size of files.

Paul

 

[Samurai]

Urlscan, not on Win2003. The old Win2000 had it, but that never caused any
problem.

 

[David Wang [Msft]]

Do you have ASP Response buffering enabled. I believe it is on by default.

And on IIS6, the default maximum ASP buffered response is 4MB. Configurable.
W3SVC/AspBufferingLimit

This limit is introduced for security reasons -- on IIS5, it is possible to
run a rogue ASP page in an infinite loop doing a Response.Write() with
buffering enabled to consume all system memory.

--
//David
IIS
http://blogs.msdn.com/David.Wang
This posting is provided "AS IS" with no warranties, and confers no rights.
//

 

[Marc]

You probably have a high tech network card sitting in that new server, try
swapping it for a 10 dollar one and see what happens. (I have seen this
exact behaviour before)