diff --git a/source/FreeRTOS_IP.c b/source/FreeRTOS_IP.c
index c1b5e53c2..fdfabe078 100644
--- a/source/FreeRTOS_IP.c
+++ b/source/FreeRTOS_IP.c
@@ -956,7 +956,7 @@ void * FreeRTOS_GetUDPPayloadBuffer_Multi( size_t uxRequestedSizeBytes,
 
         /* IF the following function should be declared in the NetworkInterface.c
          * linked in the project. */
-        pxFillInterfaceDescriptor( 0, &( xInterfaces[ 0 ] ) );
+        ( void ) pxFillInterfaceDescriptor( 0, &( xInterfaces[ 0 ] ) );
         FreeRTOS_FillEndPoint( &( xInterfaces[ 0 ] ), &( xEndPoints[ 0 ] ), ucIPAddress, ucNetMask, ucGatewayAddress, ucDNSServerAddress, ucMACAddress );
         #if ( ipconfigUSE_DHCP != 0 )
         {
diff --git a/source/portable/NetworkInterface/DriverSAM/NetworkInterface.c b/source/portable/NetworkInterface/DriverSAM/NetworkInterface.c
index db99b73ea..952e533e0 100644
--- a/source/portable/NetworkInterface/DriverSAM/NetworkInterface.c
+++ b/source/portable/NetworkInterface/DriverSAM/NetworkInterface.c
@@ -522,7 +522,7 @@ static BaseType_t prvSAM_NetworkInterfaceInitialise( NetworkInterface_t * pxInte
 }
 /*-----------------------------------------------------------*/
 
-#if defined( ipconfigIPv4_BACKWARD_COMPATIBLE ) && ( ipconfigIPv4_BACKWARD_COMPATIBLE == 1 )
+#if ( ipconfigIPv4_BACKWARD_COMPATIBLE != 0 )
 
 /* Do not call the following function directly. It is there for downward compatibility.
  * The function FreeRTOS_IPInit() will call it to initialice the interface and end-point
@@ -530,7 +530,7 @@ static BaseType_t prvSAM_NetworkInterfaceInitialise( NetworkInterface_t * pxInte
     NetworkInterface_t * pxFillInterfaceDescriptor( BaseType_t xEMACIndex,
                                                     NetworkInterface_t * pxInterface )
     {
-        pxSAM_FillInterfaceDescriptor( xEMACIndex, pxInterface );
+        return pxSAM_FillInterfaceDescriptor( xEMACIndex, pxInterface );
     }
 
 #endif
diff --git a/source/portable/NetworkInterface/MPS2_AN385/NetworkInterface.c b/source/portable/NetworkInterface/MPS2_AN385/NetworkInterface.c
index 951d33266..1c55f82db 100644
--- a/source/portable/NetworkInterface/MPS2_AN385/NetworkInterface.c
+++ b/source/portable/NetworkInterface/MPS2_AN385/NetworkInterface.c
@@ -398,7 +398,7 @@ static BaseType_t xMPS2_GetPhyLinkStatus( NetworkInterface_t * pxInterface )
 
 /*-----------------------------------------------------------*/
 
-#if ( ipconfigIPv4_BACKWARD_COMPATIBLE == 1 )
+#if ( ipconfigIPv4_BACKWARD_COMPATIBLE != 0 )
 
 /* Do not call the following function directly. It is there for downward compatibility.
  * The function FreeRTOS_IPInit() will call it to initialice the interface and end-point
@@ -406,7 +406,7 @@ static BaseType_t xMPS2_GetPhyLinkStatus( NetworkInterface_t * pxInterface )
     NetworkInterface_t * pxFillInterfaceDescriptor( BaseType_t xEMACIndex,
                                                     NetworkInterface_t * pxInterface )
     {
-        pxMPS2_FillInterfaceDescriptor( xEMACIndex, pxInterface );
+        return pxMPS2_FillInterfaceDescriptor( xEMACIndex, pxInterface );
     }
 
 #endif
diff --git a/source/portable/NetworkInterface/MPS3_AN552/NetworkInterface.c b/source/portable/NetworkInterface/MPS3_AN552/NetworkInterface.c
index 836f4e3b0..ac68594ac 100644
--- a/source/portable/NetworkInterface/MPS3_AN552/NetworkInterface.c
+++ b/source/portable/NetworkInterface/MPS3_AN552/NetworkInterface.c
@@ -507,7 +507,7 @@ static BaseType_t xLAN91C111_GetPhyLinkStatus( NetworkInterface_t * pxInterface
 
 /*-----------------------------------------------------------*/
 
-#if ( ipconfigIPv4_BACKWARD_COMPATIBLE == 1 )
+#if ( ipconfigIPv4_BACKWARD_COMPATIBLE != 0 )
 
 /* Do not call the following function directly. It is there for downward compatibility.
  * The function FreeRTOS_IPInit() will call it to initialise the interface and end-point
@@ -515,7 +515,7 @@ static BaseType_t xLAN91C111_GetPhyLinkStatus( NetworkInterface_t * pxInterface
     NetworkInterface_t * pxFillInterfaceDescriptor( BaseType_t xEMACIndex,
                                                     NetworkInterface_t * pxInterface )
     {
-        pxLAN91C111_FillInterfaceDescriptor( xEMACIndex, pxInterface );
+        return pxLAN91C111_FillInterfaceDescriptor( xEMACIndex, pxInterface );
     }
 
 #endif
diff --git a/source/portable/NetworkInterface/MPS4_CS315/NetworkInterface.c b/source/portable/NetworkInterface/MPS4_CS315/NetworkInterface.c
index 9fc319f96..ac68594ac 100644
--- a/source/portable/NetworkInterface/MPS4_CS315/NetworkInterface.c
+++ b/source/portable/NetworkInterface/MPS4_CS315/NetworkInterface.c
@@ -507,7 +507,7 @@ static BaseType_t xLAN91C111_GetPhyLinkStatus( NetworkInterface_t * pxInterface
 
 /*-----------------------------------------------------------*/
 
-#if defined( ipconfigIPv4_BACKWARD_COMPATIBLE ) && ( ipconfigIPv4_BACKWARD_COMPATIBLE == 1 )
+#if ( ipconfigIPv4_BACKWARD_COMPATIBLE != 0 )
 
 /* Do not call the following function directly. It is there for downward compatibility.
  * The function FreeRTOS_IPInit() will call it to initialise the interface and end-point
@@ -515,7 +515,7 @@ static BaseType_t xLAN91C111_GetPhyLinkStatus( NetworkInterface_t * pxInterface
     NetworkInterface_t * pxFillInterfaceDescriptor( BaseType_t xEMACIndex,
                                                     NetworkInterface_t * pxInterface )
     {
-        pxLAN91C111_FillInterfaceDescriptor( xEMACIndex, pxInterface );
+        return pxLAN91C111_FillInterfaceDescriptor( xEMACIndex, pxInterface );
     }
 
 #endif
diff --git a/source/portable/NetworkInterface/NXP1060/NetworkInterface.c b/source/portable/NetworkInterface/NXP1060/NetworkInterface.c
index 6eee8a78f..4d5097425 100644
--- a/source/portable/NetworkInterface/NXP1060/NetworkInterface.c
+++ b/source/portable/NetworkInterface/NXP1060/NetworkInterface.c
@@ -269,7 +269,7 @@ NetworkInterface_t * pxNXP1060_FillInterfaceDescriptor( BaseType_t xEMACIndex,
                                                         NetworkInterface_t * pxInterface );
 /*-----------------------------------------------------------*/
 
-#if ( ipconfigCOMPATIBLE_WITH_SINGLE != 0 )
+#if ( ipconfigIPv4_BACKWARD_COMPATIBLE != 0 )
 
 /* Do not call the following function directly. It is there for downward compatibility.
  * The function FreeRTOS_IPInit() will call it to initialice the interface and end-point
@@ -277,10 +277,10 @@ NetworkInterface_t * pxNXP1060_FillInterfaceDescriptor( BaseType_t xEMACIndex,
     NetworkInterface_t * pxFillInterfaceDescriptor( BaseType_t xEMACIndex,
                                                     NetworkInterface_t * pxInterface )
     {
-        pxNXP1060_FillInterfaceDescriptor( xEMACIndex, pxInterface );
+        return pxNXP1060_FillInterfaceDescriptor( xEMACIndex, pxInterface );
     }
 
-#endif /* ( ipconfigCOMPATIBLE_WITH_SINGLE != 0 ) */
+#endif /* ( ipconfigIPv4_BACKWARD_COMPATIBLE != 0 ) */
 /*-----------------------------------------------------------*/
 
 NetworkInterface_t * pxNXP1060_FillInterfaceDescriptor( BaseType_t xEMACIndex,
diff --git a/source/portable/NetworkInterface/STM32Fxx/NetworkInterface.c b/source/portable/NetworkInterface/STM32Fxx/NetworkInterface.c
index 8d2ed7f48..64e8071f5 100644
--- a/source/portable/NetworkInterface/STM32Fxx/NetworkInterface.c
+++ b/source/portable/NetworkInterface/STM32Fxx/NetworkInterface.c
@@ -353,7 +353,7 @@ BaseType_t xNetworkInterfaceOutput( NetworkInterface_t * pxInterface,
     return xSTM32F_NetworkInterfaceOutput( pxInterface, pxBuffer, bReleaseAfterSend );
 }
 
-#if defined( ipconfigIPv4_BACKWARD_COMPATIBLE ) && ( ipconfigIPv4_BACKWARD_COMPATIBLE == 1 )
+#if ( ipconfigIPv4_BACKWARD_COMPATIBLE != 0 )
 
 /* Do not call the following function directly. It is there for downward compatibility.
  * The function FreeRTOS_IPInit() will call it to initialice the interface and end-point
diff --git a/source/portable/NetworkInterface/STM32Hxx/NetworkInterface.c b/source/portable/NetworkInterface/STM32Hxx/NetworkInterface.c
index e0cc4f036..4456d517e 100644
--- a/source/portable/NetworkInterface/STM32Hxx/NetworkInterface.c
+++ b/source/portable/NetworkInterface/STM32Hxx/NetworkInterface.c
@@ -535,7 +535,7 @@ static BaseType_t xSTM32H_GetPhyLinkStatus( NetworkInterface_t * pxInterface )
 }
 /*-----------------------------------------------------------*/
 
-#if ( ipconfigIPv4_BACKWARD_COMPATIBLE == 1 )
+#if ( ipconfigIPv4_BACKWARD_COMPATIBLE != 0 )
 
 /* Do not call the following function directly. It is there for downward compatibility.
  * The function FreeRTOS_IPInit() will call it to initialice the interface and end-point
diff --git a/source/portable/NetworkInterface/WinPCap/NetworkInterface.c b/source/portable/NetworkInterface/WinPCap/NetworkInterface.c
index c3e4a6d3b..e7f8975a8 100644
--- a/source/portable/NetworkInterface/WinPCap/NetworkInterface.c
+++ b/source/portable/NetworkInterface/WinPCap/NetworkInterface.c
@@ -347,7 +347,7 @@ static BaseType_t xWinPcap_GetPhyLinkStatus( NetworkInterface_t * pxInterface )
 }
 /*-----------------------------------------------------------*/
 
-#if ( ipconfigIPv4_BACKWARD_COMPATIBLE == 1 )
+#if ( ipconfigIPv4_BACKWARD_COMPATIBLE != 0 )
 
 
 /* Do not call the following function directly. It is there for downward compatibility.
@@ -356,7 +356,7 @@ static BaseType_t xWinPcap_GetPhyLinkStatus( NetworkInterface_t * pxInterface )
     NetworkInterface_t * pxFillInterfaceDescriptor( BaseType_t xEMACIndex,
                                                     NetworkInterface_t * pxInterface )
     {
-        pxWinPcap_FillInterfaceDescriptor( xEMACIndex, pxInterface );
+        return pxWinPcap_FillInterfaceDescriptor( xEMACIndex, pxInterface );
     }
 
 #endif
diff --git a/source/portable/NetworkInterface/Zynq/NetworkInterface.c b/source/portable/NetworkInterface/Zynq/NetworkInterface.c
index cc1873bcb..25dfd8e0f 100644
--- a/source/portable/NetworkInterface/Zynq/NetworkInterface.c
+++ b/source/portable/NetworkInterface/Zynq/NetworkInterface.c
@@ -523,7 +523,7 @@ static BaseType_t xZynqGetPhyLinkStatus( NetworkInterface_t * pxInterface )
 }
 /*-----------------------------------------------------------*/
 
-#if ( ipconfigIPv4_BACKWARD_COMPATIBLE == 1 )
+#if ( ipconfigIPv4_BACKWARD_COMPATIBLE != 0 )
 
 /* Do not call the following function directly. It is there for downward compatibility.
  * The function FreeRTOS_IPInit() will call it to initialice the interface and end-point
@@ -531,7 +531,7 @@ static BaseType_t xZynqGetPhyLinkStatus( NetworkInterface_t * pxInterface )
     NetworkInterface_t * pxFillInterfaceDescriptor( BaseType_t xEMACIndex,
                                                     NetworkInterface_t * pxInterface )
     {
-        pxZynq_FillInterfaceDescriptor( xEMACIndex, pxInterface );
+        return pxZynq_FillInterfaceDescriptor( xEMACIndex, pxInterface );
     }
 
 #endif
diff --git a/source/portable/NetworkInterface/esp32/NetworkInterface.c b/source/portable/NetworkInterface/esp32/NetworkInterface.c
index b4c8b068e..452fad6fc 100644
--- a/source/portable/NetworkInterface/esp32/NetworkInterface.c
+++ b/source/portable/NetworkInterface/esp32/NetworkInterface.c
@@ -60,7 +60,7 @@ NetworkInterface_t * pxESP32_Eth_FillInterfaceDescriptor( BaseType_t xEMACIndex,
 
 /*-----------------------------------------------------------*/
 
-#if ( ipconfigIPv4_BACKWARD_COMPATIBLE == 1 )
+#if ( ipconfigIPv4_BACKWARD_COMPATIBLE != 0 )
 
 /* Do not call the following function directly. It is there for downward compatibility.
  * The function FreeRTOS_IPInit() will call it to initialice the interface and end-point
@@ -68,7 +68,7 @@ NetworkInterface_t * pxESP32_Eth_FillInterfaceDescriptor( BaseType_t xEMACIndex,
     NetworkInterface_t * pxFillInterfaceDescriptor( BaseType_t xEMACIndex,
                                                     NetworkInterface_t * pxInterface )
     {
-        pxESP32_Eth_FillInterfaceDescriptor( xEMACIndex, pxInterface );
+        return pxESP32_Eth_FillInterfaceDescriptor( xEMACIndex, pxInterface );
     }
 
 #endif
diff --git a/source/portable/NetworkInterface/loopback/loopbackNetworkInterface.c b/source/portable/NetworkInterface/loopback/loopbackNetworkInterface.c
index 466c6e47d..cf66a62ff 100644
--- a/source/portable/NetworkInterface/loopback/loopbackNetworkInterface.c
+++ b/source/portable/NetworkInterface/loopback/loopbackNetworkInterface.c
@@ -75,7 +75,7 @@ static BaseType_t prvLoopback_Initialise( NetworkInterface_t * pxInterface )
 }
 /*-----------------------------------------------------------*/
 
-#if ( ipconfigCOMPATIBLE_WITH_SINGLE != 0 )
+#if ( ipconfigIPv4_BACKWARD_COMPATIBLE != 0 )
 
 /* Do not call the following function directly. It is there for downward compatibility.
  * The function FreeRTOS_IPInit() will call it to initialice the interface and end-point
@@ -83,10 +83,10 @@ static BaseType_t prvLoopback_Initialise( NetworkInterface_t * pxInterface )
     NetworkInterface_t * pxFillInterfaceDescriptor( BaseType_t xEMACIndex,
                                                     NetworkInterface_t * pxInterface )
     {
-        pxLoopback_FillInterfaceDescriptor( xEMACIndex, pxInterface );
+        return pxLoopback_FillInterfaceDescriptor( xEMACIndex, pxInterface );
     }
 
-#endif /* ( ipconfigCOMPATIBLE_WITH_SINGLE != 0 ) */
+#endif /* ( ipconfigIPv4_BACKWARD_COMPATIBLE != 0 ) */
 /*-----------------------------------------------------------*/
 
 NetworkInterface_t * pxLoopback_FillInterfaceDescriptor( BaseType_t xEMACIndex,
diff --git a/source/portable/NetworkInterface/pic32mzef/NetworkInterface_eth.c b/source/portable/NetworkInterface/pic32mzef/NetworkInterface_eth.c
index c9500c5b1..df35ed880 100644
--- a/source/portable/NetworkInterface/pic32mzef/NetworkInterface_eth.c
+++ b/source/portable/NetworkInterface/pic32mzef/NetworkInterface_eth.c
@@ -219,7 +219,7 @@
         };
     #endif /* (PIC32_MAC_DEBUG_COMMANDS != 0) */
 
-    #if defined( ipconfigIPv4_BACKWARD_COMPATIBLE ) && ( ipconfigIPv4_BACKWARD_COMPATIBLE == 1 )
+    #if ( ipconfigIPv4_BACKWARD_COMPATIBLE != 0 )
 
 /* Do not call the following function directly. It is there for downward compatibility.
  * The function FreeRTOS_IPInit() will call it to initialice the interface and end-point
@@ -227,7 +227,7 @@
         NetworkInterface_t * pxFillInterfaceDescriptor( BaseType_t xEMACIndex,
                                                         NetworkInterface_t * pxInterface )
         {
-            pxPIC32_Eth_FillInterfaceDescriptor( xEMACIndex, pxInterface );
+            return pxPIC32_Eth_FillInterfaceDescriptor( xEMACIndex, pxInterface );
         }
 
     #endif