tune ttl and mtu

core/c/custom/lwipopts.h

@@ -36,6 +36,7 @@
 #define NO_SYS 1
 #define LWIP_TIMERS 1
 
+#define IP_DEFAULT_TTL 64
 #define LWIP_ARP 0
 #define ARP_QUEUEING 0
 #define IP_FORWARD 0

core/lwip.go

@@ -118,4 +118,7 @@ func init() {
 	// Now the loop interface is just the first element in
 	// `C.netif_list`, i.e. `*C.netif_list`.
 	lwipInit()
+
+	// Set MTU.
+	C.netif_list.mtu = 1500
 }