diff --git a/doc/ppp.txt b/doc/ppp.txt
index bf4673ef..f380df02 100644
--- a/doc/ppp.txt
+++ b/doc/ppp.txt
@@ -326,6 +326,17 @@ ppp_set_auth(ppp, PPPAUTHTYPE_ANY, "login", "password");
 /* Require peer to authenticate */
 ppp_set_auth_required(ppp, 1);
 
+/*
+ * Only for PPPoS, the PPP session should be up and waiting for input.
+ *
+ * Note: for PPPoS, ppp_connect() and ppp_listen() are actually the same thing.
+ * The listen call is meant for future support of PPPoE and PPPoL2TP server
+ * mode, where we will need to negotiate the incoming PPPoE session or L2TP
+ * session before initiating PPP itself. We need this call because there is
+ * two passive modes for PPPoS, ppp_set_passive and ppp_set_silent.
+ */
+ppp_set_silent(pppos, 1);
+
 /*
  * Initiate PPP listener (i.e. wait for an incoming connection), can only
  * be called if PPP session is in the dead state (i.e. disconnected).
diff --git a/src/include/netif/ppp/ppp.h b/src/include/netif/ppp/ppp.h
index 862b8269..ac7bee42 100644
--- a/src/include/netif/ppp/ppp.h
+++ b/src/include/netif/ppp/ppp.h
@@ -509,6 +509,20 @@ void ppp_set_mppe(ppp_pcb *pcb, u8_t flags);
  */
 #define ppp_set_listen_time(ppp, intval) (ppp->settings.listen_time = intval)
 
+/*
+ * Enables the "passive" option in the LCP. With this option, we will attempt
+ * to initiate a connection; if no reply is received from the peer, we will
+ * then just wait passively for a valid LCP packet from the peer.
+ */
+#define ppp_set_passive(ppp, boolval) (ppp->lcp_wantoptions.passive = boolval)
+
+/*
+ * With this option, we will not transmit LCP packets to initiate a connection
+ * until a valid LCP packet is received from the peer. This is what we usually
+ * call the server mode.
+ */
+#define ppp_set_silent(ppp, boolval) (ppp->lcp_wantoptions.silent = boolval)
+
 /*
  * Set a PPP interface as the default network interface
  * (used to output all packets for which no specific route is found).
diff --git a/src/netif/ppp/ppp.c b/src/netif/ppp/ppp.c
index c0d2004b..fe7d544b 100644
--- a/src/netif/ppp/ppp.c
+++ b/src/netif/ppp/ppp.c
@@ -288,18 +288,12 @@ err_t ppp_connect(ppp_pcb *pcb, u16_t holdoff) {
  * established before calling this.
  */
 err_t ppp_listen(ppp_pcb *pcb) {
-  lcp_options *lcp_wo;
-
   if (pcb->phase != PPP_PHASE_DEAD) {
     return ERR_ALREADY;
   }
 
   PPPDEBUG(LOG_DEBUG, ("ppp_listen[%d]\n", pcb->netif->num));
 
-  /* Wait passively */
-  lcp_wo = &pcb->lcp_wantoptions;
-  lcp_wo->silent = 1;
-
   if (pcb->link_cb->listen) {
     return pcb->link_cb->listen(pcb, pcb->link_ctx_cb);
   }