Co-existing ASP.NET 1.1 and 2.0???



Hi all --

We currently have an ecommerce application installed on a W2K Advanced
server running .NET 1.1.

In November, I installed .NET 2.0 in order to allow a Windows Forms
application I wrote to be run on the server for extracting system

We have recently had an issue with our ecommerce application where we would
experience high CPU utilization and customers would begin calling in to
complain about slow response After looking into our EventLogs and audit
logs for our ASP.NET 1.1 apps, I would have a bunch of SOAP error messages
and connection fails, etc.

From my understanding of the application, when users log into our website,
we also access a third party's website at the same time using SOAP.

We later found out that third party had changed their IP address via DNS and
our firewall was blocking our servers outbound connection. We were
basically down over the weekend until Monday afternoon until we realized the

We then made the necessary firewall change and flushed the DNS cache. We
started receiving the correct IP address.

However, we were still experiencing some issues -- especially with something
internal to our application. It somehow displays a hyperlink to the end
user to our third party based on some condition. I'm not exactly sure what
that condition is. But...

Our IT department that wrote the software is blaming the issues that we have
been having from having the .NET 2.0 framework installed. This was likely
because the EventLog reports a message about "Unable to access Shim
Database..." message. According to Microsoft KB, this is a known issue and
has to do with read/write access to the registry. There is a hotfix, but I
never applied, since it appeared not to be an issue for us. Anyway, the IT
folks finally removed .NET 2.0 and the application and hyperlinks began
working correctly again.

All of the applications were configured to use ASP.NET 1.1 framework with
Internet Service Manager.

I'm currently debating with our IT folks that the problem was not related to
have 2.0 installed (it has been installed since last November!) and it was a
coincendence that application started working.

They are also telling me that they have seen "strange things happen" when
the 2.0 framework is installed on ecommerce servers running their
applications. I cannot get them to define strange... but this sounds like

From my basic understanding of .NET and writing a few programs in C# using
Forms and ASP.NET, I see no incompatibility issues with having both
frameworks installed side-by-side.

Isn't this the very essence of having a separate distributable runtime for
each release? So you don't break existing applications?

I've basically been banned from re-installing 2.0 on our web server because
of this incident.

I think this is totally ridiculous and cannot receive any concrete facts as
to what strange problems they experience and how the 2.0 framework messes up
their application. To me it seems like an easy answer.

I know the root cause has to do with their SOAP access to the vendor and
somehow when DNS does not resolve or there is a connectivity issue, it
causes the server to get bogged down due to the volume of logins that occur
with mutiple sessions attempting to do the same thing.

They have no response as of yet.

Does anyone have any opinions on this issue?

Can .NET 1.1 and 2.0 apps co-exist without issues????

....irate in IT land!




As far as I can tell, since our organization has both 1.1 and 2.0 Framework
ASP.NET applications running off the same IIS instance, they can co-exist
quite peacefully.
The most important thing I can recommend is that you should have 2.0 apps
and 1.1 apps assigned to separate appPools in IIS. Otherwise, as long as the
scriptmaps for a particular application are set to the correct framework. I
haven't seen any such issues.

It's easy to point blame on something due to lack of knowledge or experience.

In a few cases, it is something completely unrelated that is actually
causing the problem.

So, tell your IT folks to be more specific about documenting exactly what
their issue is.

Co-founder, developer portal:


Thanks for the feedback.

The funny thing is... I have no ASP.NET 2.0 apps installed on the server.
Our ecommerce application only uses 1.1.

I do require .NET 2.0 Framework installed due to a WinForm application that
I had written. That's it.

So I have no idea why they think .NET 2.0 is causing the issues. They
uninstalled and are saying the app worked when removed. So that was the

I think it was a coincidence myself.

Morten Wennevik

After installing framework 2.0, you might want to double check that the
web application isn't set to run as 2.0. There should be a new ASP.NET
tab in the web application properties.

I believe there are cases where upgrading to 2.0 will auto upgrade web
application and you then have to use /noaspupgrade when installing
framework 2.0

Mark Harris

It could be that a windows update that came down and updated your .net
install set the virtual directory or virtual server to .net 2.0 instead of
1.1 - breaking the ecomm app, when you uninstalled it set itself back.



Dylan Parry

Morten said:
I believe there are cases where upgrading to 2.0 will auto upgrade web
application and you then have to use /noaspupgrade when installing
framework 2.0

On a similar line, does anyone happen to remember how to make 2.0 the
*default* for all new web applications in IIS? I did find it once, but
subsequent searches after reinstalling my machine turned out to be
fruitless :(


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