diff --git a/doc/changelog.txt b/doc/changelog.txt
index dfab91a..f8826c7 100644
--- a/doc/changelog.txt
+++ b/doc/changelog.txt
@@ -2,6 +2,7 @@
 HEAD
 ====
 - xt_TARPIT: fix kernel warning about RTAX_HOPLIMIT being used
+- xt_TEE: abort build when the feature is already provided by mainline
 
 
 v1.37 (2011-06-25)
diff --git a/extensions/xt_TEE.c b/extensions/xt_TEE.c
index 0d9edb1..fb9538f 100644
--- a/extensions/xt_TEE.c
+++ b/extensions/xt_TEE.c
@@ -14,6 +14,7 @@
 #include <linux/module.h>
 #include <linux/route.h>
 #include <linux/skbuff.h>
+#include <linux/version.h>
 #include <net/checksum.h>
 #include <net/icmp.h>
 #include <net/ip.h>
@@ -21,6 +22,13 @@
 #include <net/route.h>
 #include <linux/netfilter/x_tables.h>
 
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 35)
+#	error ----------------------------------------------------------
+#	error This module has been merged into, and is available in the
+#	error mainline since Linux kernel v2.6.35. Please use that.
+#	error ----------------------------------------------------------
+#endif
+
 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
 #	define WITH_CONNTRACK 1
 #	include <net/netfilter/nf_conntrack.h>