diff --git a/src/include/netif/ppp/ppp_impl.h b/src/include/netif/ppp/ppp_impl.h
index 4cb6e79b..7d959dba 100644
--- a/src/include/netif/ppp/ppp_impl.h
+++ b/src/include/netif/ppp/ppp_impl.h
@@ -462,7 +462,9 @@ int sif6up(ppp_pcb *pcb);
 int sif6down (ppp_pcb *pcb);
 #endif /* PPP_IPV6_SUPPORT */
 
+#if DEMAND_SUPPORT
 int sifnpmode(ppp_pcb *pcb, int proto, enum NPmode mode);
+#endif /* DEMAND_SUPPORt */
 
 void netif_set_mtu(ppp_pcb *pcb, int mtu);
 int netif_get_mtu(ppp_pcb *pcb);
diff --git a/src/netif/ppp/ipcp.c b/src/netif/ppp/ipcp.c
index 1ae343ea..b694c756 100644
--- a/src/netif/ppp/ipcp.c
+++ b/src/netif/ppp/ipcp.c
@@ -2050,7 +2050,9 @@ static void ipcp_up(fsm *f) {
 	    return;
 	}
 #endif
+#if DEMAND_SUPPORT
 	sifnpmode(pcb, PPP_IP, NPMODE_PASS);
+#endif /* DEMAND_SUPPORT */
 
 #if 0 /* UNUSED */
 	/* assign a default route through the interface if required */
@@ -2147,7 +2149,9 @@ static void ipcp_down(fsm *f) {
     } else
 #endif /* DEMAND_SUPPORT */
     {
+#if DEMAND_SUPPORT
 	sifnpmode(pcb, PPP_IP, NPMODE_DROP);
+#endif /* DEMAND_SUPPORT */
 	sifdown(pcb);
 	ipcp_clear_addrs(pcb, go->ouraddr,
 			 ho->hisaddr, 0);
diff --git a/src/netif/ppp/ipv6cp.c b/src/netif/ppp/ipv6cp.c
index 38805228..ca0b1b57 100644
--- a/src/netif/ppp/ipv6cp.c
+++ b/src/netif/ppp/ipv6cp.c
@@ -1240,7 +1240,9 @@ static void ipv6cp_up(fsm *f) {
 	    ipv6cp_close(f->pcb, "Interface configuration failed");
 	    return;
 	}
+#if DEMAND_SUPPORT
 	sifnpmode(f->pcb, PPP_IPV6, NPMODE_PASS);
+#endif /* DEMAND_SUPPORT */
 
 	ppp_notice("local  LL address %s", llv6_ntoa(go->ourid));
 	ppp_notice("remote LL address %s", llv6_ntoa(ho->hisid));
@@ -1295,7 +1297,9 @@ static void ipv6cp_down(fsm *f) {
     } else
 #endif /* DEMAND_SUPPORT */
     {
+#if DEMAND_SUPPORT
 	sifnpmode(f->pcb, PPP_IPV6, NPMODE_DROP);
+#endif /* DEMAND_SUPPORT */
 	ipv6cp_clear_addrs(f->pcb,
 			   go->ourid,
 			   ho->hisid);
diff --git a/src/netif/ppp/ppp.c b/src/netif/ppp/ppp.c
index 5272a76f..9bcaa3a2 100644
--- a/src/netif/ppp/ppp.c
+++ b/src/netif/ppp/ppp.c
@@ -1265,6 +1265,7 @@ int sif6down(ppp_pcb *pcb) {
 }
 #endif /* PPP_IPV6_SUPPORT */
 
+#if DEMAND_SUPPORT
 /*
  * sifnpmode - Set the mode for handling packets for a given NP.
  */
@@ -1274,6 +1275,7 @@ int sifnpmode(ppp_pcb *pcb, int proto, enum NPmode mode) {
   LWIP_UNUSED_ARG(mode);
   return 0;
 }
+#endif /* DEMAND_SUPPORT */
 
 /*
  * netif_set_mtu - set the MTU on the PPP network interface.