diff --git a/src/include/netif/ppp/ppp.h b/src/include/netif/ppp/ppp.h
index bf41bde0..bfa9ed6f 100644
--- a/src/include/netif/ppp/ppp.h
+++ b/src/include/netif/ppp/ppp.h
@@ -359,9 +359,9 @@ struct ppp_pcb_s {
 
 #if PPP_AUTH_SUPPORT
   /* auth data */
-#if PPP_SERVER
+#if PPP_SERVER && defined(HAVE_MULTILINK)
   char peer_authname[MAXNAMELEN + 1]; /* The name by which the peer authenticated itself to us. */
-#endif /* PPP_SERVER */
+#endif /* PPP_SERVER && defined(HAVE_MULTILINK) */
   u16_t auth_pending;        /* Records which authentication operations haven't completed yet. */
   u16_t auth_done;           /* Records which authentication operations have been completed. */
 
diff --git a/src/netif/ppp/auth.c b/src/netif/ppp/auth.c
index 593843e6..6735e1e3 100644
--- a/src/netif/ppp/auth.c
+++ b/src/netif/ppp/auth.c
@@ -1045,6 +1045,10 @@ void auth_peer_fail(ppp_pcb *pcb, int protocol) {
  */
 void auth_peer_success(ppp_pcb *pcb, int protocol, int prot_flavor, const char *name, int namelen) {
     int bit;
+#ifndef HAVE_MULTILINK
+    LWIP_UNUSED_ARG(name);
+    LWIP_UNUSED_ARG(namelen);
+#endif /* HAVE_MULTILINK */
 
     switch (protocol) {
 #if CHAP_SUPPORT
@@ -1082,14 +1086,15 @@ void auth_peer_success(ppp_pcb *pcb, int protocol, int prot_flavor, const char *
 	return;
     }
 
+#ifdef HAVE_MULTILINK
     /*
      * Save the authenticated name of the peer for later.
      */
-    /* FIXME: do we need that ? */
     if (namelen > (int)sizeof(pcb->peer_authname) - 1)
 	namelen = (int)sizeof(pcb->peer_authname) - 1;
     MEMCPY(pcb->peer_authname, name, namelen);
     pcb->peer_authname[namelen] = 0;
+#endif /* HAVE_MULTILINK */
 #if 0 /* UNUSED */
     script_setenv("PEERNAME", , 0);
 #endif /* UNUSED */