diff -up ./doc/config/conf.d/ssi.conf.orig ./doc/config/conf.d/ssi.conf
--- ./doc/config/conf.d/ssi.conf.orig	2017-01-29 12:25:34.058705498 +0200
+++ ./doc/config/conf.d/ssi.conf	2017-01-29 12:27:29.974314712 +0200
@@ -8,6 +8,11 @@
 server.modules += ( "mod_ssi" )
 
 ##
+## files to check for if .../ is requested
+##
+index-file.names += ( "index.shtml" )
+
+##
 ## which extensions should be ran through mod_ssi.
 ##
 ssi.extension              = ( ".shtml" )