diff --git a/libretro-common/include/net/net_natt.h b/libretro-common/include/net/net_natt.h
index d3b2c43560..4a48ba0795 100644
--- a/libretro-common/include/net/net_natt.h
+++ b/libretro-common/include/net/net_natt.h
@@ -65,12 +65,6 @@ bool natt_new(struct natt_status *status);
 /** Free a NAT traversal status object */
 void natt_free(struct natt_status *status);
 
-/**
- * Make a port forwarding request. This may finish immediately or just send a
- * request to the network. */
-bool natt_open_port(struct natt_status *status, struct sockaddr *addr,
-   socklen_t addrlen, enum socket_protocol proto);
-
 /**
  * Make a port forwarding request when only the port is known. Forwards any
  * address it can find. */
diff --git a/libretro-common/net/net_natt.c b/libretro-common/net/net_natt.c
index 01e6cc94f7..5ea34e1652 100644
--- a/libretro-common/net/net_natt.c
+++ b/libretro-common/net/net_natt.c
@@ -94,7 +94,8 @@ void natt_free(struct natt_status *status)
    /* Nothing */
 }
 
-bool natt_open_port(struct natt_status *status, struct sockaddr *addr, socklen_t addrlen, enum socket_protocol proto)
+static bool natt_open_port(struct natt_status *status,
+      struct sockaddr *addr, socklen_t addrlen, enum socket_protocol proto)
 {
 #ifndef HAVE_SOCKET_LEGACY
 #if HAVE_MINIUPNPC