diff --git a/CHANGES b/CHANGES
index 13c1d3b..b7c2daf 100644
--- a/CHANGES
+++ b/CHANGES
@@ -86,6 +86,9 @@ corrections:
 	fixed a bug that could lead to error or socat crash after a client
 	connection with option retry had been established
 
+	fixed configure.in bug on net/if.h check that caused IF_NAMESIZE to be
+	undefined
+
 	docu mentions option so-bindtodev but correct name is so-bindtodevice. 
 	Thanks to Jim Zimmerman for reporting.
 
diff --git a/configure.in b/configure.in
index ded7833..9f3faa4 100644
--- a/configure.in
+++ b/configure.in
@@ -64,7 +64,7 @@ AC_CHECK_HEADERS(netinet/ip.h, [], [], [AC_INCLUDES_DEFAULT
 	#include <netinet/in_systm.h>
 	#endif])        # Solaris prerequisites for netinet/ip.h
 AC_CHECK_HEADERS(netinet/tcp.h)
-AC_CHECK_HEADER(net/if.h, [], [], [AC_INCLUDES_DEFAULT
+AC_CHECK_HEADER(net/if.h, AC_DEFINE(HAVE_NET_IF_H), [], [AC_INCLUDES_DEFAULT
 	#if HAVE_SYS_SOCKET_H
 	#include <sys/socket.h>
 	#endif])	# Mac OS X requires including sys/socket.h