diff --git a/cores/esp8266/LwipIntfDev.h b/cores/esp8266/LwipIntfDev.h
index 94e3e71c63..b6679f709a 100644
--- a/cores/esp8266/LwipIntfDev.h
+++ b/cores/esp8266/LwipIntfDev.h
@@ -96,7 +96,7 @@ class LwipIntfDev: public LwipIntf, public RawDev
     {
         return IPAddress(ip4_addr_get_u32(ip_2_ip4(&_netif.gw)));
     }
-    IPAddress dnsIP(int n) const  // WiFi lib way
+    IPAddress dnsIP(int n = 0) const  // WiFi lib way
     {
         return IPAddress(dns_getserver(n));
     }