--- src/siproxd.c
+++ src/siproxd.c
@@ -236,6 +236,18 @@
    if (read_config(configfile, config_search, main_cfg_opts, "") == STS_FAILURE) {
       exit(1);
    }
+   /* add trailing slash to configuration.plugin_dir if missing */
+   if (configuration.plugin_dir) {
+      int len = strlen(configuration.plugin_dir);
+      if (len && configuration.plugin_dir[len-1] != '/') {
+         char *tmp = (char*)malloc(len+2);
+         memcpy(tmp, configuration.plugin_dir, len);
+         tmp[len] = '/';
+         tmp[len+1] = '\0';
+         free(configuration.plugin_dir);
+         configuration.plugin_dir = tmp;
+      }
+   }
    /* remember where config file is located, so the plugins
     * can load it as well - if required */
    configuration.configfile = strdup(configfile);