diff --git a/idle_scan.cc b/idle_scan.cc
index ca21d5e84..3ba06bf7b 100644
--- a/idle_scan.cc
+++ b/idle_scan.cc
@@ -104,6 +104,8 @@
 #include "utils.h"
 #include "output.h"
 
+#include "struct_ip.h"
+
 #include <stdio.h>
 
 extern NmapOps o;
diff --git a/nmap.h b/nmap.h
index d2d3bbf86..01a3bbdc9 100644
--- a/nmap.h
+++ b/nmap.h
@@ -150,20 +150,6 @@ void *realloc();
 #include <sys/param.h> /* Defines MAXHOSTNAMELEN on BSD*/
 #endif
 
-/* Linux uses these defines in netinet/ip.h to use the correct struct ip */
-#ifndef __FAVOR_BSD
-#define __FAVOR_BSD
-#endif
-#ifndef __USE_BSD
-#define __USE_BSD
-#endif
-#ifndef _BSD_SOURCE
-#define _BSD_SOURCE
-#endif
-
-/* BSDI needs this to insure the correct struct ip */
-#undef _IP_VHL
-
 #include <stdio.h>
 
 #if HAVE_RPC_TYPES_H
@@ -204,16 +190,6 @@ void *realloc();
 #include <pwd.h>
 #endif
 
-#ifndef NETINET_IN_SYSTM_H  /* This guarding is needed for at least some versions of OpenBSD */
-#include <netinet/in_systm.h> /* defines n_long needed for netinet/ip.h */
-#define NETINET_IN_SYSTM_H
-#endif
-#ifndef NETINET_IP_H  /* This guarding is needed for at least some versions of OpenBSD */
-#include <netinet/ip.h> 
-#define NETINET_IP_H
-#endif
-// #include <netinet/ip_icmp.h> 
-
 #if HAVE_ARPA_INET_H
 #include <arpa/inet.h>
 #endif
diff --git a/nse_dnet.cc b/nse_dnet.cc
index 5b4ebfe56..e867e899f 100644
--- a/nse_dnet.cc
+++ b/nse_dnet.cc
@@ -9,6 +9,8 @@
 #include "nse_main.h"
 #include "nse_utility.h"
 
+#include "struct_ip.h"
+
 extern "C" {
 #include "lua.h"
 #include "lauxlib.h"
diff --git a/osscan2.cc b/osscan2.cc
index 190df77d0..e0b307f98 100644
--- a/osscan2.cc
+++ b/osscan2.cc
@@ -99,6 +99,9 @@
 #include "utils.h"
 #include "FPEngine.h"
 #include <dnet.h>
+
+#include "struct_ip.h"
+
 #include <list>
 
 using namespace std;
diff --git a/scan_engine.cc b/scan_engine.cc
index 4655e984f..272c3b5d8 100644
--- a/scan_engine.cc
+++ b/scan_engine.cc
@@ -105,6 +105,9 @@
 #include "Target.h"
 #include "targets.h"
 #include "utils.h"
+
+#include "struct_ip.h"
+
 #include <math.h>
 #include <list>
 #include <map>
diff --git a/struct_ip.h b/struct_ip.h
new file mode 100644
index 000000000..0eeb58598
--- /dev/null
+++ b/struct_ip.h
@@ -0,0 +1,45 @@
+/* The C library on AIX defines the names of various members of struct ip to
+   something else in <netinet/ip.h>:
+
+struct ip {
+	struct	ip_firstfour ip_ff;
+#define	ip_v	ip_ff.ip_fv
+#define	ip_hl	ip_ff.ip_fhl
+#define	ip_vhl	ip_ff.ip_fvhl
+#define	ip_tos	ip_ff.ip_ftos
+#define	ip_len	ip_ff.ip_flen
+
+   This breaks code that actually wants to use names like ip_v for its own
+   purposes, like struct ip_hdr in libdnet. The AIX definitions will work
+   if they are included late in the list of includes, before other code that
+   might want to use the above names has already been preprocessed. The
+   includes that end up defining struct ip are therefore limited to this
+   file, so it can be included in a .cc file after other .h have been
+   included. */
+
+/* Linux uses these defines in netinet/ip.h to use the correct struct ip */
+#ifndef __FAVOR_BSD
+#define __FAVOR_BSD
+#endif
+#ifndef __USE_BSD
+#define __USE_BSD
+#endif
+#ifndef _BSD_SOURCE
+#define _BSD_SOURCE
+#endif
+
+/* BSDI needs this to insure the correct struct ip */
+#undef _IP_VHL
+
+#ifndef NETINET_IN_SYSTM_H  /* This guarding is needed for at least some versions of OpenBSD */
+#include <netinet/in_systm.h> /* defines n_long needed for netinet/ip.h */
+#define NETINET_IN_SYSTM_H
+#endif
+#ifndef NETINET_IP_H  /* This guarding is needed for at least some versions of OpenBSD */
+#include <netinet/ip.h>
+#define NETINET_IP_H
+#endif
+
+#ifndef WIN32
+#include <netinet/ip_icmp.h>
+#endif
diff --git a/tcpip.cc b/tcpip.cc
index 6c5835b15..fab1af998 100644
--- a/tcpip.cc
+++ b/tcpip.cc
@@ -103,6 +103,7 @@
 #include "Target.h"
 #include "utils.h"
 
+#include "struct_ip.h"
 
 #if HAVE_SYS_TIME_H
 #include <sys/time.h>
diff --git a/tcpip.h b/tcpip.h
index 2482a274f..82911821d 100644
--- a/tcpip.h
+++ b/tcpip.h
@@ -133,19 +133,6 @@ void *realloc();
 #include <sys/param.h> /* Defines MAXHOSTNAMELEN on BSD*/
 #endif
 
-/* Linux uses these defines in netinet/ip.h to use the correct struct ip */
-#ifndef __FAVOR_BSD
-#define __FAVOR_BSD 1
-#endif
-#ifndef _BSD_SOURCE
-#define _BSD_SOURCE 1
-#endif
-#ifndef __USE_BSD
-#define __USE_BSD 1
-#endif
-/* BSDI needs this to insure the correct struct ip */
-#undef _IP_VHL
-
 #include <stdio.h>
 
 #if HAVE_NETINET_IN_H
@@ -165,14 +152,6 @@ void *realloc();
 #endif
 
 #include <arpa/inet.h>
-#ifndef NETINET_IN_SYSTM_H  /* This guarding is needed for at least some versions of OpenBSD */
-#include <netinet/in_systm.h> /* defines n_long needed for netinet/ip.h */
-#define NETINET_IN_SYSTM_H
-#endif
-#ifndef NETINET_IP_H  /* This guarding is needed for at least some versions of OpenBSD */
-#include <netinet/ip.h>
-#define NETINET_IP_H
-#endif
 #if HAVE_UNISTD_H
 #include <unistd.h>
 #endif
@@ -208,9 +187,6 @@ extern "C" {
 #include <errno.h>
 #include <signal.h>
 #include <dnet.h>
-#ifndef WIN32
-#include <netinet/ip_icmp.h>
-#endif
 
 
 
diff --git a/traceroute.cc b/traceroute.cc
index 371eb5860..fafb7a67d 100644
--- a/traceroute.cc
+++ b/traceroute.cc
@@ -137,6 +137,8 @@ individually.
 #include "NmapOps.h"
 #include "Target.h"
 
+#include "struct_ip.h"
+
 #include <dnet.h>
 
 #include <algorithm>
@@ -145,6 +147,33 @@ individually.
 #include <set>
 #include <vector>
 
+/* Linux uses these defines in netinet/ip.h to use the correct struct ip */
+#ifndef __FAVOR_BSD
+#define __FAVOR_BSD
+#endif
+#ifndef __USE_BSD
+#define __USE_BSD
+#endif
+#ifndef _BSD_SOURCE
+#define _BSD_SOURCE
+#endif
+
+/* BSDI needs this to insure the correct struct ip */
+#undef _IP_VHL
+
+#ifndef NETINET_IN_SYSTM_H  /* This guarding is needed for at least some versions of OpenBSD */
+#include <netinet/in_systm.h> /* defines n_long needed for netinet/ip.h */
+#define NETINET_IN_SYSTM_H
+#endif
+#ifndef NETINET_IP_H  /* This guarding is needed for at least some versions of OpenBSD */
+#include <netinet/ip.h> 
+#define NETINET_IP_H
+#endif
+
+#ifndef WIN32
+#include <netinet/ip_icmp.h>
+#endif
+
 extern NmapOps o;
 
 /* The highest TTL we go up to if the target itself doesn't respond. */