diff --git a/net/devif/devif_forward.c b/net/devif/devif_forward.c
index 4f93ee3cbbb..8a1a1bd855c 100644
--- a/net/devif/devif_forward.c
+++ b/net/devif/devif_forward.c
@@ -41,6 +41,7 @@
 #include <assert.h>
 #include <debug.h>
 
+#include <nuttx/mm/iob.h>
 #include <nuttx/net/netdev.h>
 
 #include "ipforward/ipforward.h"
diff --git a/net/ipforward/ipforward.h b/net/ipforward/ipforward.h
index 52069b80abe..a267c1f9016 100644
--- a/net/ipforward/ipforward.h
+++ b/net/ipforward/ipforward.h
@@ -44,16 +44,6 @@
 
 #include <stdint.h>
 
-#include <nuttx/net/ip.h>
-#include <nuttx/net/udp.h>
-#include <nuttx/net/tcp.h>
-#include <nuttx/net/icmp.h>
-#include <nuttx/net/icmpv6.h>
-
-#include "udp/udp.h"
-#include "tcp/tcp.h"
-#include "icmpv6/icmpv6.h"
-
 #undef HAVE_FWDALLOC
 #ifdef CONFIG_NET_IPFORWARD
 
@@ -73,68 +63,10 @@
 #  define CONFIG_NET_IPFORWARD_NSTRUCT 4
 #endif
 
-#define FWD_HEADER(fwd) (FAR union fwd_iphdr_u *)((fwd)->f_iob->io_data)
-
 /****************************************************************************
  * Public Types
  ****************************************************************************/
 
-/* IPv4 + L2 header */
-
-#ifdef CONFIG_NET_IPv4
-struct fwd_ipv4hdr_u
-{
-  struct ipv4_hdr_s       l2;
-  union
-  {
-#ifdef CONFIG_NET_TCP
-    uint8_t               pad[TCP_MAX_HDRLEN];
-    struct tcp_hdr_s      tcp;
-#endif
-#ifdef CONFIG_NET_UDP
-    struct udp_hdr_s      udp;
-#endif
-#ifdef CONFIG_NET_ICMPv6
-    struct icmp_hdr_s     icmp;
-#endif
-  } l3;
-};
-#endif
-
-/* IPv6 + L2 header */
-
-#ifdef CONFIG_NET_IPv6
-struct fwd_ipv6hdr_u
-{
-  struct ipv6_hdr_s       l2;
-  union
-  {
-#ifdef CONFIG_NET_TCP
-    uint8_t               pad[TCP_MAX_HDRLEN];
-    struct tcp_hdr_s      tcp;
-#endif
-#ifdef CONFIG_NET_UDP
-    struct udp_hdr_s      udp;
-#endif
-#ifdef CONFIG_NET_ICMPv6
-    struct icmpv6_hdr_s   icmpv6;
-#endif
-  } l3;
-};
-#endif
-
-/* IPv4 or IPv6 + L2 header */
-
-union fwd_iphdr_u
-{
-#ifdef CONFIG_NET_IPv4
-  struct fwd_ipv4hdr_u  ipv4;
-#endif
-#ifdef CONFIG_NET_IPv6
-  struct fwd_ipv6hdr_u  ipv6;
-#endif
-};
-
 /* This is the send state structure */
 
 struct devif_callback_s; /* Forward refernce */
@@ -156,6 +88,9 @@ struct forward_s
  * Public Function Prototypes
  ****************************************************************************/
 
+struct ipv4_hdr_s; /* Forward reference */
+struct ipv6_hdr_s; /* Forward reference */
+
 /****************************************************************************
  * Name: ipfwd_initialize
  *
diff --git a/net/ipforward/ipfwd_alloc.c b/net/ipforward/ipfwd_alloc.c
index 01e34099e47..e2265db19ff 100644
--- a/net/ipforward/ipfwd_alloc.c
+++ b/net/ipforward/ipfwd_alloc.c
@@ -44,10 +44,37 @@
 #include <errno.h>
 #include <debug.h>
 
+#include <nuttx/net/tcp.h>
+#include <nuttx/net/udp.h>
+#include <nuttx/net/icmp.h>
+#include <nuttx/net/icmpv6.h>
+
 #include "ipforward/ipforward.h"
 
 #if defined(CONFIG_NET_IPFORWARD) &&  defined(CONFIG_NETDEV_MULTINIC)
 
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+#ifdef CONFIG_NET_IPv6
+#  define L2_MAXHDRLEN IPv6_HDRLEN
+#else
+#  define L2_MAXHDRLEN IPv4_HDRLEN
+#endif
+
+#if defined(CONFIG_NET_TCP)
+#  define L3_MAXHDRLEN TCP_MAX_HDRLEN
+#elif defined(CONFIG_NET_UDP)
+#  define L3_MAXHDRLEN UDP_HDRLEN
+#elif defined(CONFIG_NET_ICMPv6)
+#  define L3_MAXHDRLEN ICMPv6_HDRLEN
+#elif defined(CONFIG_NET_ICMP)
+#  define L3_MAXHDRLEN ICMP_HDRLEN
+#endif
+
+#define MAX_HDRLEN (L2_MAXHDRLEN + L3_MAXHDRLEN)
+
 /****************************************************************************
  * Private Data
  ****************************************************************************/
@@ -84,7 +111,7 @@ void ipfwd_initialize(void)
    * the contiguous memory of the first IOB in the IOB chain.
    */
 
-  DEBUGASSERT(sizeof(union fwd_iphdr_u) <= CONFIG_IOB_BUFSIZE);
+  DEBUGASSERT(MAX_HDRLEN <= CONFIG_IOB_BUFSIZE);
 
   /* Add all pre-allocated forwarding structures to the free list */
 
diff --git a/net/ipforward/ipfwd_forward.c b/net/ipforward/ipfwd_forward.c
index c7e1156b105..962713425e4 100644
--- a/net/ipforward/ipfwd_forward.c
+++ b/net/ipforward/ipfwd_forward.c
@@ -144,8 +144,6 @@ static inline void forward_ipselect(FAR struct forward_s *fwd)
 #ifdef CONFIG_NET_ETHERNET
 static inline bool ipfwd_addrchk(FAR struct forward_s *fwd)
 {
-  FAR union fwd_iphdr_u *iphdr;
-
   DEBUGASSERT(fwd != NULL && fwd->f_iob != NULL && fwd->f_dev != NULL);
 
   /* REVISIT: Could the MAC address not also be in a routing table? */
@@ -157,15 +155,14 @@ static inline bool ipfwd_addrchk(FAR struct forward_s *fwd)
     }
 #endif
 
-  iphdr = FWD_HEADER(fwd);
-
 #ifdef CONFIG_NET_IPv4
 #ifdef CONFIG_NET_IPv6
   if (fwd->f_domain == PF_INET)
 #endif
     {
 #if !defined(CONFIG_NET_ARP_IPIN) && !defined(CONFIG_NET_ARP_SEND)
-      return (arp_find(iphdr->ipv4.l2.destipaddr) != NULL);
+      FAR stuct ipv4_hdr_s *ipv4 = (FAR stuct ipv4_hdr_s *)fwd->f_iob->io_data;
+      return (arp_find(ipv4->destipaddr) != NULL);
 #else
       return true;
 #endif
@@ -178,7 +175,8 @@ static inline bool ipfwd_addrchk(FAR struct forward_s *fwd)
 #endif
     {
 #if !defined(CONFIG_NET_ICMPv6_NEIGHBOR)
-      return (neighbor_findentry(iphdr->ipv6.l2.destipaddr) != NULL);
+      FAR stuct ipv6_hdr_s *ipv4 = (FAR stuct ipv6_hdr_s *)fwd->f_iob->io_data;
+      return (neighbor_findentry(ipv6->destipaddr) != NULL);
 #else
       return true;
 #endif