diff --git a/src/include/netif/ppp_oe.h b/src/include/netif/ppp_oe.h
index e1cdfa51..c8b15d46 100644
--- a/src/include/netif/ppp_oe.h
+++ b/src/include/netif/ppp_oe.h
@@ -133,13 +133,6 @@ PACK_STRUCT_END
 #define PPPOE_CODE_PADS       0x65    /* Active Discovery Session confirmation */
 #define PPPOE_CODE_PADT       0xA7    /* Active Discovery Terminate */
 
-#ifndef ETHERMTU
-#define ETHERMTU 1500
-#endif
-
-/* two byte PPP protocol discriminator, then IP data */
-#define PPPOE_MAXMTU          (ETHERMTU-PPPOE_HEADERLEN-2)
-
 #ifndef PPPOE_MAX_AC_COOKIE_LEN
 #define PPPOE_MAX_AC_COOKIE_LEN   64
 #endif
diff --git a/src/netif/ppp/ppp.c b/src/netif/ppp/ppp.c
index be6d61c3..ea8fabaa 100644
--- a/src/netif/ppp/ppp.c
+++ b/src/netif/ppp/ppp.c
@@ -609,12 +609,12 @@ int ppp_over_ethernet_open(struct netif *ethif, const char *service_name, const
     pc->link_status_cb  = link_status_cb;
     pc->link_status_ctx = link_status_ctx;
 
-    lcp_wantoptions[pd].mru = PPPOE_MAXMTU;
+    lcp_wantoptions[pd].mru = ethif->mtu-PPPOE_HEADERLEN-2; /* two byte PPP protocol discriminator, then IP data */
     lcp_wantoptions[pd].neg_asyncmap = 0;
     lcp_wantoptions[pd].neg_pcompression = 0;
     lcp_wantoptions[pd].neg_accompression = 0;
 
-    lcp_allowoptions[pd].mru = PPPOE_MAXMTU;
+    lcp_allowoptions[pd].mru = ethif->mtu-PPPOE_HEADERLEN-2; /* two byte PPP protocol discriminator, then IP data */
     lcp_allowoptions[pd].neg_asyncmap = 0;
     lcp_allowoptions[pd].neg_pcompression = 0;
     lcp_allowoptions[pd].neg_accompression = 0;