diff --git a/Socket/NetdeviceController.cc b/Socket/NetdeviceController.cc
index a11c494d019cd6f366ac6e1018e3c7a6e539a60b..b93998c044ff21daa3bee505d468bfe45d95be0c 100644
--- a/Socket/NetdeviceController.cc
+++ b/Socket/NetdeviceController.cc
@@ -52,6 +52,7 @@ prefix_ senf::NetdeviceController::NetdeviceController(int interface_index)
 }
 
 prefix_ std::string senf::NetdeviceController::interfaceName()
+    const
 {
     struct ifreq ifr;
     ifrName( ifr);
@@ -59,6 +60,7 @@ prefix_ std::string senf::NetdeviceController::interfaceName()
 }
 
 prefix_ senf::MACAddress senf::NetdeviceController::hardwareAddress()
+    const
 {
     struct ifreq ifr;
     ifrName( ifr);
@@ -67,6 +69,7 @@ prefix_ senf::MACAddress senf::NetdeviceController::hardwareAddress()
 }
 
 prefix_ int senf::NetdeviceController::mtu()
+    const
 {
     struct ifreq ifr;
     ifrName( ifr);
@@ -75,6 +78,7 @@ prefix_ int senf::NetdeviceController::mtu()
 }
 
 prefix_ void senf::NetdeviceController::mtu(int new_mtu)
+    const
 {
     struct ifreq ifr;
     ifrName( ifr);
@@ -83,6 +87,7 @@ prefix_ void senf::NetdeviceController::mtu(int new_mtu)
 }
 
 prefix_ int senf::NetdeviceController::interfaceIndex()
+    const
 {
     return ifindex_;
 }
@@ -100,6 +105,7 @@ prefix_ void senf::NetdeviceController::openSocket()
 }
 
 prefix_ void senf::NetdeviceController::ifrName(ifreq& ifr)
+    const
 {
     ::memset( &ifr, 0, sizeof(ifr));
     ifr.ifr_ifindex = ifindex_;
@@ -109,6 +115,7 @@ prefix_ void senf::NetdeviceController::ifrName(ifreq& ifr)
 
 
 prefix_ void senf::NetdeviceController::doIoctl(ifreq& ifr, int request)
+    const
 {
     if ( ::ioctl( sockfd_, request, &ifr ) < 0 )
         throw SystemException();
diff --git a/Socket/NetdeviceController.hh b/Socket/NetdeviceController.hh
index 1db86556102381eec3eed7e6de371226d1af4af9..dbc5ce6154c3dcbcfb4559ccdc1f853f2ef358ac 100644
--- a/Socket/NetdeviceController.hh
+++ b/Socket/NetdeviceController.hh
@@ -50,16 +50,16 @@ namespace senf {
         NetdeviceController(int interface_index);
         virtual ~NetdeviceController();
         
-        MACAddress hardwareAddress();
-        std::string interfaceName();
-        int interfaceIndex(); ///< return the interface index of the interface
-        int mtu();
-        void mtu(int new_mtu);
+        MACAddress hardwareAddress() const;
+        std::string interfaceName() const;
+        int interfaceIndex() const; ///< return the interface index of the interface
+        int mtu() const;
+        void mtu(int new_mtu) const;
     
     private:
         void openSocket();
-        void doIoctl(ifreq& ifr, int request);
-        void ifrName(ifreq& ifr);
+        void doIoctl(ifreq& ifr, int request) const;
+        void ifrName(ifreq& ifr) const;
         int sockfd_;
         int ifindex_;
     };