diff --git a/ports/unix/netif/tcpdump.c b/ports/unix/netif/tcpdump.c
index 7699480..0267663 100644
--- a/ports/unix/netif/tcpdump.c
+++ b/ports/unix/netif/tcpdump.c
@@ -73,7 +73,6 @@ tcpdump(struct pbuf *p)
   if (file == NULL) {
     return;
   }
-#ifdef IPv4
   iphdr = (struct ip_hdr *)p->payload;
   switch (IPH_PROTO(iphdr)) {
 #if LWIP_TCP
@@ -184,7 +183,6 @@ tcpdump(struct pbuf *p)
     break;
 
   }
-#endif /* IPv4 */
 }
 /*-----------------------------------------------------------------------------------*/
 
diff --git a/ports/unix/proj/lib/Makefile b/ports/unix/proj/lib/Makefile
index 4c61cce..04a457d 100644
--- a/ports/unix/proj/lib/Makefile
+++ b/ports/unix/proj/lib/Makefile
@@ -39,7 +39,7 @@ LWIPDIR=$(CONTRIBDIR)/../lwip/src
 
 CCDEP=gcc
 CC=gcc
-CFLAGS=-g -Wall -DIPv4 -DLWIP_DEBUG -fPIC -pedantic -Werror \
+CFLAGS=-g -Wall -DLWIP_DEBUG -fPIC -pedantic -Werror \
 	-Wparentheses -Wsequence-point -Wswitch-default \
 	-Wextra -Wundef -Wshadow -Wpointer-arith -Wbad-function-cast \
 	-Wc++-compat -Wwrite-strings -Wold-style-definition \
diff --git a/ports/unix/proj/minimal/Makefile b/ports/unix/proj/minimal/Makefile
index b4020eb..31bbb65 100644
--- a/ports/unix/proj/minimal/Makefile
+++ b/ports/unix/proj/minimal/Makefile
@@ -35,7 +35,7 @@ CC=gcc
 #To compile for cygwin: make ARCH=cygwin
 #To compile for openbsd: make ARCH=openbsd
 ARCH=openbsd
-CFLAGS=-g -Wall -D$(ARCH) -DIPv4 -Os -DLWIP_DEBUG -pedantic -Werror \
+CFLAGS=-g -Wall -D$(ARCH) -Os -DLWIP_DEBUG -pedantic -Werror \
 	-Wparentheses -Wsequence-point -Wswitch-default \
 	-Wextra -Wundef -Wshadow -Wpointer-arith -Wbad-function-cast \
 	-Wc++-compat -Wwrite-strings -Wold-style-definition \
diff --git a/ports/unix/proj/unixsim/Makefile b/ports/unix/proj/unixsim/Makefile
index 8a18fe6..5aa3c72 100644
--- a/ports/unix/proj/unixsim/Makefile
+++ b/ports/unix/proj/unixsim/Makefile
@@ -35,7 +35,7 @@ CC=gcc
 #To compile for linux: make ARCH=linux
 #To compile for cygwin: make ARCH=cygwin
 ARCH=unix
-CFLAGS=-g -Wall -D$(ARCH) -DIPv4 -DLWIP_DEBUG -pedantic -Werror \
+CFLAGS=-g -Wall -D$(ARCH) -DLWIP_DEBUG -pedantic -Werror \
 	-Wparentheses -Wsequence-point -Wswitch-default \
 	-Wextra -Wundef -Wshadow -Wpointer-arith -Wbad-function-cast \
 	-Wc++-compat -Wwrite-strings -Wold-style-definition \