--- src/proxsmtpd.c
+++ src/proxsmtpd.c
@@ -385,8 +385,12 @@
         sp_setup_forked(sp, 1);
         
         /* Now run the filter command */
-        execl("/bin/sh", "sh", "-c", g_pxstate.command, NULL);
-        
+        if  ((g_pxstate.command[0] == '/') && !index(g_pxstate.command, ' ')) {
+            execl(g_pxstate.command, g_pxstate.command, NULL);
+        } else {
+            execl("/bin/sh", "sh", "-c", g_pxstate.command, NULL);
+        }
+
         /* If that returned then there was an error */
         sp_message(sp, LOG_ERR, "error executing the shell for filter command");
         kill_myself();