Ticket #25106: 25106.2.diff

wp-admin/network.php

@@ -409 +409 @@
                 // IIS doesn't support RewriteBase, all your RewriteBase are belong to us
                 $iis_subdir_match = ltrim( $base, '/' ) . $subdir_match;
                 $iis_rewrite_base = ltrim( $base, '/' ) . $rewrite_base;
-                $iis_subdir_replacement = $subdomain_install ? '' : '{R:1}';
+                $iis_subdir_replacement = $subdomain_install ? '/' . ltrim( $iis_rewrite_base, '/' ) : '{R:1}';
 
                 $web_config_file = '<?xml version="1.0" encoding="UTF-8"?>
 <configuration>