diff --git a/lib/Makefile.vc6 b/lib/Makefile.vc6
index 0abdd7607..ed1e241b2 100644
--- a/lib/Makefile.vc6
+++ b/lib/Makefile.vc6
@@ -109,6 +109,10 @@ CFGSET     = FALSE
 CFLAGS = $(CFLAGS) /DUSE_WINDOWS_SSPI /I$(WINDOWS_SDK_PATH)\include
 !ENDIF
 
+!IFDEF USE_IPV6
+CFLAGS = $(CFLAGS) /DUSE_IPV6
+!ENDIF
+
 ##############################################################
 # Runtime library configuration
 
diff --git a/lib/config-win32.h b/lib/config-win32.h
index 0c254707a..8c6f91a9f 100644
--- a/lib/config-win32.h
+++ b/lib/config-win32.h
@@ -569,7 +569,7 @@
 /* Name of package */
 #define PACKAGE "curl"
 
-#if defined(__POCC__)
+#if defined(__POCC__) || (USE_IPV6)
 #  define ENABLE_IPV6 1
 #endif