diff --git a/dlls/nsiproxy.sys/ip.c b/dlls/nsiproxy.sys/ip.c
index ab1b6294bea..93fdefa24cc 100644
--- a/dlls/nsiproxy.sys/ip.c
+++ b/dlls/nsiproxy.sys/ip.c
@@ -21,6 +21,10 @@
 #include "config.h"
 #include <stdarg.h>
 
+#ifdef HAVE_SYS_SOCKET_H
+#include <sys/socket.h>
+#endif
+
 #ifdef HAVE_NETINET_IN_H
 #include <netinet/in.h>
 #endif