Error Message: No peer endpoint available to which to send SAML response

[Peter Schober]

* Yu Chen <cheny18 at rpi.edu> [2014-06-18 06:14]:
> We've got some problems while trying to have multiple websites under
> protection of a single SP. We configured our machine following the
> instruction here
> https://wiki.shibboleth.net/confluence/display/SHIB2/NativeSPApplicationOverride. 
> 
> Basically, we have one physical machine and there are 3 domain names bundle
> with it, say A.edu, B.edu and C.edu. And we want to have
> https://A.edu/secure/test.php, https://B.edu/secure/test.php,
> https://C.edu/secure/test.php.

That in itself is not a use-case for ApplicationOverride. Sessions
will be partitioned by vhost anyway simply by the fact that a
conforming HTTP User Agent will not transmit HTTP Cookies set by
example-A.edu to a host named example-B.edu.
The simplest thing you can do in that case is adding additional ACS
Locations for all other vhosts to an existing SP's EntityDescriptor.

You usually only need Overrides for partitioning sessions on the same
vhost, or to serve have several logical SAML SPs from one install.
The latter would be the case if a SAML IDP needed to differentiate
between those logical SPs, e.g. by issuing them different sets of SAML
attributes.
Given that all data ends up on the same box and in the same software
instance (and in the same storage service on the server) of course
it's much easier to just send the union of all needed attributes to
the SP and deal with the attributes on the application level.
-peter