Log errors for invalid interface values

deluge/core/core.py

@@ -126,9 +126,12 @@ class Core(component.Component):
         # If there was an interface value from the command line, use it, but
         # store the one in the config so we can restore it on shutdown
         self.__old_interface = None
-        if listen_interface and deluge.common.is_ip(listen_interface):
-            self.__old_interface = self.config["listen_interface"]
-            self.config["listen_interface"] = listen_interface
+        if listen_interface:
+            if deluge.common.is_ip(listen_interface):
+                self.__old_interface = self.config["listen_interface"]
+                self.config["listen_interface"] = listen_interface
+            else:
+                log.error("Invalid listen interface (must be IP Address): %s", listen_interface)
 
     def start(self):
         """Starts the core"""

deluge/core/daemon.py

@@ -98,9 +98,6 @@ class Daemon(object):
                     return 1
             SetConsoleCtrlHandler(win_handler)
 
-        if listen_interface and not is_ip(listen_interface):
-            listen_interface = None
-
         # Start the core as a thread and join it until it's done
         self.core = Core(listen_interface=listen_interface)
 
@@ -108,6 +105,7 @@ class Daemon(object):
             port = self.core.config["daemon_port"]
 
         if interface and not is_ip(interface):
+            log.error("Invalid UI interface (must be IP Address): %s", interface)
             interface = None
 
         self.rpcserver = RPCServer(