diff --git a/src/include/os/sun4/osiSock.h b/src/include/os/sun4/osiSock.h
index b34c11e20..edf2ffb30 100644
--- a/src/include/os/sun4/osiSock.h
+++ b/src/include/os/sun4/osiSock.h
@@ -17,6 +17,7 @@ extern "C" {
 #include <sys/ioctl.h>
 #include <netinet/in.h>
 #include <netinet/tcp.h>
+#include <net/if.h>
  
 int ioctl (int fd, int req, ...);
 int close (int fd);
diff --git a/src/libCom/osi/os/sun4/osdSock.h b/src/libCom/osi/os/sun4/osdSock.h
index b34c11e20..edf2ffb30 100644
--- a/src/libCom/osi/os/sun4/osdSock.h
+++ b/src/libCom/osi/os/sun4/osdSock.h
@@ -17,6 +17,7 @@ extern "C" {
 #include <sys/ioctl.h>
 #include <netinet/in.h>
 #include <netinet/tcp.h>
+#include <net/if.h>
  
 int ioctl (int fd, int req, ...);
 int close (int fd);