diff --git a/mongoose.h b/mongoose.h
index 92391c62..7929b588 100644
--- a/mongoose.h
+++ b/mongoose.h
@@ -2805,6 +2805,7 @@ void mg_tcpip_arp_request(struct mg_tcpip_if *ifp, uint32_t ip, uint8_t *mac);
 
 extern struct mg_tcpip_driver mg_tcpip_driver_stm32f;
 extern struct mg_tcpip_driver mg_tcpip_driver_w5500;
+extern struct mg_tcpip_driver mg_tcpip_driver_w5100;
 extern struct mg_tcpip_driver mg_tcpip_driver_tm4c;
 extern struct mg_tcpip_driver mg_tcpip_driver_tms570;
 extern struct mg_tcpip_driver mg_tcpip_driver_stm32h;
diff --git a/src/net_builtin.h b/src/net_builtin.h
index 47109770..f9f6e5e9 100644
--- a/src/net_builtin.h
+++ b/src/net_builtin.h
@@ -71,6 +71,7 @@ void mg_tcpip_arp_request(struct mg_tcpip_if *ifp, uint32_t ip, uint8_t *mac);
 
 extern struct mg_tcpip_driver mg_tcpip_driver_stm32f;
 extern struct mg_tcpip_driver mg_tcpip_driver_w5500;
+extern struct mg_tcpip_driver mg_tcpip_driver_w5100;
 extern struct mg_tcpip_driver mg_tcpip_driver_tm4c;
 extern struct mg_tcpip_driver mg_tcpip_driver_tms570;
 extern struct mg_tcpip_driver mg_tcpip_driver_stm32h;