Shibboleth SP IIS Error 2746

Lukas Hämmerle lukas.haemmerle at
Wed May 27 08:20:13 EDT 2015

On 12.05.15 16:30, Lukas Hämmerle wrote:
>>> However, maybe someone has a better debugging idea or can extend that
>>> list of known ISAPI filters/extensions that conflict with Shib.
>> What filters are installed that aren't default things?
> Thanks Scott. I'll try to figure that out (don't have direct access to
> the system).

An update on this issue:
After various tests/re-installations it seems that the difference
between a system that has no problems with the Shib login and one that
has problems is the two modules:

* ASPxHttpHandlerModule

* ASPxUploadProgressHttpHandler

Both are part of the DevExpress HTTP Handler and it seems that in our
case both are (locally) loaded by the application's web.config. This
also means that removing the application get's rid of the problem
(Shibboleth login and access to a protected directory works again).

We suspect that it is rather the ASPxHttpHandlerModule (maybe due to the
compressing [1] functionality it contains) that causes this problem but
we have to yet to dig a bit more... One reason, I'm posting this is
because others might face the same very annoying and time-consuming problem.

Best Regards


Lukas Hämmerle, Central Solutions
GÉANT Project Task Leader "Enabling Users"
Werdstrasse 2, P.O. Box, 8021 Zurich, Switzerland
phone +41 44 268 15 05, direct +41 44 268 15 64
lukas.haemmerle at,

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