diff --git a/include/lwipopts.h b/include/lwipopts.h
index 532dff0..c720a52 100644
--- a/include/lwipopts.h
+++ b/include/lwipopts.h
@@ -48,7 +48,6 @@
 #if defined(LIBZT_IPV6)
 	#define LWIP_IPV6   1
  	#define LWIP_IPV4   0
-
 #endif
 #if defined(LIBZT_IPV4) 
 	#define LWIP_IPV4   1
diff --git a/make-liblwip.mk b/make-liblwip.mk
index f2079d4..a12b5a4 100644
--- a/make-liblwip.mk
+++ b/make-liblwip.mk
@@ -44,11 +44,9 @@ ifeq ($(origin CCX),default)
 	CCX=$(shell if [ -e /usr/bin/clang++ ]; then echo clang++; else echo g++; fi)
 endif
 
-CFLAGS=-O3 -g -Wall -DIPv4 -DIPv6 -fPIC
+CFLAGS=-O3 -g -Wall -fPIC
 
-CFLAGS:=$(CFLAGS) \
-	-I$(LWIPDIR)/include -I$(LWIPARCH)/include -I$(LWIPDIR)/include/ipv4 \
-	-I$(LWIPDIR) -I. -Iext -Iinclude
+CFLAGS:=$(CFLAGS) -I$(LWIPDIR)/include -I$(LWIPARCH)/include -I$(LWIPDIR) -I. -Iext -Iinclude
 
 # COREFILES, CORE4FILES: The minimum set of files needed for lwIP.
 COREFILES=$(LWIPDIR)/core/init.c \
@@ -68,7 +66,6 @@ COREFILES=$(LWIPDIR)/core/init.c \
 	$(LWIPDIR)/core/tcp_out.c \
 	$(LWIPDIR)/core/timeouts.c \
 	$(LWIPDIR)/core/udp.c
-
 CORE4FILES=$(LWIPDIR)/core/ipv4/autoip.c \
 	$(LWIPDIR)/core/ipv4/dhcp.c \
 	$(LWIPDIR)/core/ipv4/etharp.c \
@@ -77,7 +74,6 @@ CORE4FILES=$(LWIPDIR)/core/ipv4/autoip.c \
 	$(LWIPDIR)/core/ipv4/ip4_frag.c \
 	$(LWIPDIR)/core/ipv4/ip4.c \
 	$(LWIPDIR)/core/ipv4/ip4_addr.c
-
 CORE6FILES=$(LWIPDIR)/core/ipv6/ethip6.c \
 	$(LWIPDIR)/core/ipv6/icmp6.c \
 	$(LWIPDIR)/core/ipv6/inet6.c \
@@ -87,7 +83,6 @@ CORE6FILES=$(LWIPDIR)/core/ipv6/ethip6.c \
 	$(LWIPDIR)/core/ipv6/mld6.c \
 	$(LWIPDIR)/core/ipv6/dhcp6.c \
 	$(LWIPDIR)/core/ipv6/nd6.c
-
 	# APIFILES: The files which implement the sequential and socket APIs.
 APIFILES=$(LWIPDIR)/api/api_lib.c \
 	$(LWIPDIR)/api/api_msg.c \
@@ -97,30 +92,22 @@ APIFILES=$(LWIPDIR)/api/api_lib.c \
 	$(LWIPDIR)/api/netifapi.c \
 	$(LWIPDIR)/api/sockets.c \
 	$(LWIPDIR)/api/tcpip.c
-
-
 # NETIFFILES: Files implementing various generic network interface functions
 NETIFFILES=$(LWIPDIR)/netif/ethernet.c 
-
-#
-#	$(LWIPDIR)/netif/slipif.c
-
 # SIXLOWPAN: 6LoWPAN
 SIXLOWPAN=$(LWIPDIR)/netif/lowpan6.c \
-
 # ARCHFILES: Architecture specific files.
 ARCHFILES=$(wildcard $(LWIPARCH)/*.c $(LWIPARCH)tapif.c $(LWIPARCH)/netif/list.c $(LWIPARCH)/netif/tcpdump.c)
-
 # LWIPFILES: All the above.
 LWIPFILES=$(COREFILES) $(APIFILES) $(NETIFFILES) $(ARCHFILES)
 
-ifeq ($(IPV4),1)
+ifeq ($(LIBZT_IPV4),1)
 	LWIPFILES+=$(CORE4FILES)
-	CFLAGS+=-DLIBZT_IPV4=1
+	CFLAGS+=-DLIBZT_IPV4=1 -DLWIP_IPV4 -DDLWIP_IPV6=0 -DIPv4
 endif
-ifeq ($(IPV6),1)
+ifeq ($(LIBZT_IPV6),1)
 	LWIPFILES+=$(CORE6FILES)
-	CFLAGS+=-DLIBZT_IPV6=1
+	CFLAGS+=-DLIBZT_IPV6=1 -DLWIP_IPV6 -DLWIP_IPV4=0 -DIPv6
 endif
 
 LWIPFILESW=$(wildcard $(LWIPFILES))
@@ -136,7 +123,6 @@ clean:
 	rm -f *.o *.s .depend* *.core core
 
 depend dep: .depend
-
 include .depend
 
 liblwip.a: $(LWIPOBJS)
diff --git a/make-linux.mk b/make-linux.mk
index 811229c..5acb952 100644
--- a/make-linux.mk
+++ b/make-linux.mk
@@ -121,15 +121,15 @@ ifeq ($(STACK_PICO),1)
 ifeq ($(LIBZT_IPV4)$(LIBZT_IPV6),1)
 ifeq ($(LIBZT_IPV4),1)
 CXXFLAGS+=-DLIBZT_IPV4
-STACK_FLAGS+=-IPV4=1 -IPv4=1
+STACK_FLAGS+=IPV4=1
 endif
 ifeq ($(LIBZT_IPV6),1)
 CXXFLAGS+=-DLIBZT_IPV6
-STACK_FLAGS+=-IPV6=1 -IPv6=1
+STACK_FLAGS+=IPV6=1
 endif
 else
 CXXFLAGS+=-DLIBZT_IPV4 -DLIBZT_IPV6
-STACK_FLAGS+=-IPV6=1 -IPv6=1 -IPV6=1 -IPv6=1
+STACK_FLAGS+=IPV6=1 IPV4=1
 endif
 endif
 
@@ -137,21 +137,20 @@ endif
 ifeq ($(STACK_LWIP),1)
 ifeq ($(LIBZT_IPV4)$(LIBZT_IPV6),1)
 ifeq ($(LIBZT_IPV4),1)
-CXXFLAGS+=-DLIBZT_IPV4
-STACK_FLAGS+=IPV4=1 IPv4=1
+CXXFLAGS+=-DLIBZT_IPV4 -DLWIP_IPV4=1
+STACK_FLAGS+=LIBZT_IPV4=1
 endif
 ifeq ($(LIBZT_IPV6),1)
-CXXFLAGS+=-DLIBZT_IPV6
-STACK_FLAGS+=IPV6=1 IPv6=1
+CXXFLAGS+=-DLIBZT_IPV6 -DLWIP_IPV6=1
+STACK_FLAGS+=LIBZT_IPV6=1
 endif
 else
-CXXFLAGS+=-DLIBZT_IPV4
-STACK_FLAGS+=IPV4=1 IPv4=1
+CXXFLAGS+=-DLIBZT_IPV4 -DLWIP_IPV4=1
+STACK_FLAGS+=LIBZT_IPV4=1
 endif
 endif
 
 LIBZT_FILES:=src/SocketTap.cpp src/libzt.cpp src/Utilities.cpp
-LIBZT_OBJS+=SocketTap.o libzt.o Utilities.o 
 
 ifeq ($(STACK_PICO),1)
 CXXFLAGS+=-DSTACK_PICO
@@ -159,7 +158,6 @@ STACK_LIB:=libpicotcp.a
 STACK_DIR:=ext/picotcp
 STACK_LIB:=$(STACK_DIR)/build/lib/$(STACK_LIB)
 STACK_DRIVER_FILES:=src/picoTCP.cpp
-STACK_DRIVER_OBJS+=picoTCP.o
 INCLUDES+=-Iext/picotcp/include -Iext/picotcp/build/include
 endif
 
@@ -167,7 +165,6 @@ ifeq ($(STACK_LWIP),1)
 STACK_DRIVER_FLAGS+=-DLWIP_PREFIX_BYTEORDER_FUNCS
 CXXFLAGS+=-DSTACK_LWIP
 STACK_DRIVER_FILES:=src/lwIP.cpp
-STACK_DRIVER_OBJS+=lwIP.o
 LWIPARCH=$(CONTRIBDIR)/ports/unix
 LWIPDIR=ext/lwip/src
 INCLUDES+=-Iext/lwip/src/include/lwip \
@@ -200,6 +197,7 @@ picotcp:
 	cd $(STACK_DIR); make lib ARCH=shared IPV4=1 IPV6=1
 
 lwip:
+	echo $(STACK_FLAGSs)
 	-make -f make-liblwip.mk liblwip.a $(STACK_FLAGS)
 
 ##############################################################################
@@ -211,8 +209,8 @@ static_lib: picotcp $(ZTO_OBJS)
 	@mkdir -p $(BUILD) obj
 	$(CXX) $(CXXFLAGS) $(LIBZT_FILES) $(STACK_DRIVER_FILES) -c
 	mv *.o obj
-	mv ext/picotcp/build/lib/*.o obj
-	mv ext/picotcp/build/modules/*.o obj
+	#mv ext/picotcp/build/lib/*.o obj
+	#mv ext/picotcp/build/modules/*.o obj
 	ar rcs -o $(STATIC_LIB) obj/*.o $(STACK_LIB)
 endif
 ifeq ($(STACK_LWIP),1)
@@ -258,16 +256,10 @@ tests: $(UNIT_TEST_OBJ_FILES)
 ## Misc                                                                     ##
 ##############################################################################
 
-# Cleans only current $(OSTYPE)
 clean:
 	-rm -rf $(BUILD)/*
 	-find . -type f \( -name '*.a' -o -name '*.o' -o -name '*.so' -o -name '*.o.d' -o -name '*.out' -o -name '*.log' -o -name '*.dSYM' \) -delete
 
-# Clean everything
-nuke:
-	-rm -rf $(BUILD)/*
-	-find . -type f \( -name '*.o' -o -name '*.so' -o -name '*.a' -o -name '*.o.d' -o -name '*.out' -o -name '*.log' -o -name '*.dSYM' \) -delete
-
 check:
 	-./check.sh $(PICO_LIB)
 	-./check.sh $(STATIC_LIB)
diff --git a/make-mac.mk b/make-mac.mk
index f2cd99b..22c6d11 100644
--- a/make-mac.mk
+++ b/make-mac.mk
@@ -119,37 +119,37 @@ ifeq ($(STACK_PICO),1)
 ifeq ($(LIBZT_IPV4)$(LIBZT_IPV6),1)
 ifeq ($(LIBZT_IPV4),1)
 CXXFLAGS+=-DLIBZT_IPV4
-STACK_FLAGS+=-IPV4=1 -IPv4=1
+STACK_FLAGS+=IPV4=1
 endif
 ifeq ($(LIBZT_IPV6),1)
 CXXFLAGS+=-DLIBZT_IPV6
-STACK_FLAGS+=-IPV6=1 -IPv6=1
+STACK_FLAGS+=IPV6=1
 endif
 else
 CXXFLAGS+=-DLIBZT_IPV4 -DLIBZT_IPV6
-STACK_FLAGS+=-IPV6=1 -IPv6=1 -IPV6=1 -IPv6=1
+STACK_FLAGS+=IPV6=1 IPV4=1
 endif
 endif
 
 # lwIP default protocol versions
+# Simultaneous IPV4 and IPV6 not supported by lwIP stack driver (yet)
 ifeq ($(STACK_LWIP),1)
 ifeq ($(LIBZT_IPV4)$(LIBZT_IPV6),1)
 ifeq ($(LIBZT_IPV4),1)
-CXXFLAGS+=-DLIBZT_IPV4
-STACK_FLAGS+=IPV4=1 IPv4=1
+CXXFLAGS+=-DLIBZT_IPV4 -DLWIP_IPV4=1 -DLWIP_IPV6=0
+STACK_FLAGS+=LIBZT_IPV4=1
 endif
 ifeq ($(LIBZT_IPV6),1)
-CXXFLAGS+=-DLIBZT_IPV6
-STACK_FLAGS+=IPV6=1 IPv6=1
+CXXFLAGS+=-DLIBZT_IPV6 -DLWIP_IPV6=1 -DLWIP_IPV4=0
+STACK_FLAGS+=LIBZT_IPV6=1
 endif
 else
-CXXFLAGS+=-DLIBZT_IPV4
-STACK_FLAGS+=IPV4=1 IPv4=1
+CXXFLAGS+=-DLIBZT_IPV4 -DLWIP_IPV4=1 -DLWIP_IPV6=0
+STACK_FLAGS+=LIBZT_IPV4=1
 endif
 endif
 
 LIBZT_FILES:=src/SocketTap.cpp src/libzt.cpp src/Utilities.cpp
-LIBZT_OBJS+=SocketTap.o libzt.o Utilities.o 
 
 ifeq ($(STACK_PICO),1)
 CXXFLAGS+=-DSTACK_PICO
@@ -157,7 +157,6 @@ STACK_LIB:=libpicotcp.a
 STACK_DIR:=ext/picotcp
 STACK_LIB:=$(STACK_DIR)/build/lib/$(STACK_LIB)
 STACK_DRIVER_FILES:=src/picoTCP.cpp
-STACK_DRIVER_OBJS+=picoTCP.o
 INCLUDES+=-Iext/picotcp/include -Iext/picotcp/build/include
 endif
 
@@ -165,7 +164,6 @@ ifeq ($(STACK_LWIP),1)
 STACK_DRIVER_FLAGS+=-DLWIP_PREFIX_BYTEORDER_FUNCS
 CXXFLAGS+=-DSTACK_LWIP
 STACK_DRIVER_FILES:=src/lwIP.cpp
-STACK_DRIVER_OBJS+=lwIP.o
 LWIPARCH=$(CONTRIBDIR)/ports/unix
 LWIPDIR=ext/lwip/src
 INCLUDES+=-Iext/lwip/src/include/lwip \
@@ -210,8 +208,8 @@ static_lib: picotcp $(ZTO_OBJS)
 	@mkdir -p $(BUILD) obj
 	$(CXX) $(CXXFLAGS) $(LIBZT_FILES) $(STACK_DRIVER_FILES) -c
 	mv *.o obj
-	mv ext/picotcp/build/lib/*.o obj
-	mv ext/picotcp/build/modules/*.o obj
+	#mv ext/picotcp/build/lib/*.o obj
+	#mv ext/picotcp/build/modules/*.o obj
 	libtool -static -o $(STATIC_LIB) obj/*.o $(STACK_LIB)
 endif
 ifeq ($(STACK_LWIP),1)
@@ -242,10 +240,6 @@ macos_app_framework:
 	cd examples/apple/ZeroTierSDK_Apple; xcodebuild -configuration Release -scheme ZeroTierSDK_OSX build SYMROOT="../../../$(BUILD)/macos_app_framework"
 	cd examples/apple/ZeroTierSDK_Apple; xcodebuild -configuration Debug -scheme ZeroTierSDK_OSX build SYMROOT="../../../$(BUILD)/macos_app_framework"
 
-##############################################################################
-## Static Libraries                                                         ##
-##############################################################################
-
 ##############################################################################
 ## Java JNI                                                                 ##
 ##############################################################################
@@ -273,16 +267,10 @@ tests: $(UNIT_TEST_OBJ_FILES)
 ## Misc                                                                     ##
 ##############################################################################
 
-# Cleans only current $(OSTYPE)
 clean:
 	-rm -rf $(BUILD)/*
 	-find . -type f \( -name '*.a' -o -name '*.o' -o -name '*.so' -o -name '*.o.d' -o -name '*.out' -o -name '*.log' -o -name '*.dSYM' \) -delete
 
-# Clean everything
-nuke:
-	-rm -rf $(BUILD)/*
-	-find . -type f \( -name '*.o' -o -name '*.so' -o -name '*.a' -o -name '*.o.d' -o -name '*.out' -o -name '*.log' -o -name '*.dSYM' \) -delete
-	
 check:
 	-./check.sh $(PICO_LIB)
 	-./check.sh $(STATIC_LIB)
diff --git a/src/lwIP.hpp b/src/lwIP.hpp
index c1d1e21..d38c18a 100644
--- a/src/lwIP.hpp
+++ b/src/lwIP.hpp
@@ -51,7 +51,7 @@ struct tcp_pcb;
 struct netif;
 
 #if defined(LIBZT_IPV4)
-	#define LWIP_NETIF_ADD_SIG struct netif *netif, ip_addr_t *ipaddr, ip_addr_t *netmask, ip_addr_t *gw, void *state, netif_init_fn init, netif_input_fn input
+	//#define LWIP_NETIF_ADD_SIG struct netif *netif, ip_addr_t *ipaddr, ip_addr_t *netmask, ip_addr_t *gw, void *state, netif_init_fn init, netif_input_fn input
 	#define LWIP_ETHARP_OUTPUT_SIG struct netif *netif, struct pbuf *q, const ip4_addr_t *ipaddr
 #endif
 #if defined(LIBZT_IPV6)
@@ -83,7 +83,6 @@ struct netif;
 #define LWIP_TCP_NEW_SIG void
 #define LWIP_TCP_RECV_SIG struct tcp_pcb * pcb, err_t (* recv)(void * arg, struct tcp_pcb * tpcb, struct pbuf * p, err_t err)
 #define LWIP_TCP_RECVED_SIG struct tcp_pcb * pcb, u16_t len
-//#define LWIP_TCP_SNDBUF_SIG struct tcp_pcb * pcb
 #define LWIP_TCP_CONNECT_SIG struct tcp_pcb * pcb, const ip_addr_t * ipaddr, u16_t port, err_t (* connected)(void * arg, struct tcp_pcb * tpcb, err_t err)
 #define LWIP_TCP_RECV_SIG struct tcp_pcb * pcb, err_t (* recv)(void * arg, struct tcp_pcb * tpcb, struct pbuf * p, err_t err)
 #define LWIP_TCP_ERR_SIG struct tcp_pcb * pcb, void (* err)(void * arg, err_t err)