diff --git a/src/include/gpxe/ethernet.h b/src/include/gpxe/ethernet.h
index 0188ac81..158fe066 100644
--- a/src/include/gpxe/ethernet.h
+++ b/src/include/gpxe/ethernet.h
@@ -12,6 +12,8 @@
 
 extern struct ll_protocol ethernet_protocol;
 
+extern const char * eth_ntoa ( const void *ll_addr );
+
 /**
  * Allocate Ethernet device
  *
diff --git a/src/net/ethernet.c b/src/net/ethernet.c
index 4cdf571c..690b2218 100644
--- a/src/net/ethernet.c
+++ b/src/net/ethernet.c
@@ -93,7 +93,7 @@ static int eth_rx ( struct pk_buff *pkb, struct net_device *netdev ) {
  * @v ll_addr	Link-layer address
  * @ret string	Link-layer address in human-readable format
  */
-static const char * eth_ntoa ( const void *ll_addr ) {
+const char * eth_ntoa ( const void *ll_addr ) {
 	static char buf[18]; /* "00:00:00:00:00:00" */
 	const uint8_t *eth_addr = ll_addr;