diff --git a/configure.ac b/configure.ac
index 8ac5ac4b..e808cb41 100644
--- a/configure.ac
+++ b/configure.ac
@@ -414,12 +414,6 @@ AC_CHECK_TYPES(
 	[AC_DEFINE([in_addr_t], [uint32_t], [Workaround missing in_addr_t])],
 	[[${SOCKET_INCLUDES}]]
 )
-AC_CHECK_TYPE(
-	[struct tun_pi],
-	[AC_DEFINE([HAVE_TUN_PI], [1], [struct tun_pi needed for IPv6 support])],
-	,
-	[[${SOCKET_INCLUDES}]]
-)
 AC_CHECK_TYPE(
 	[struct iphdr],
 	[AC_DEFINE([HAVE_IPHDR], [1], [struct iphdr needed for IPv6 support])],
diff --git a/src/openvpn/tun.c b/src/openvpn/tun.c
index 227bfdea..633150fe 100644
--- a/src/openvpn/tun.c
+++ b/src/openvpn/tun.c
@@ -1373,14 +1373,6 @@ close_tun_generic (struct tuntap *tt)
 #error header file linux/sockios.h required
 #endif
 
-#if defined(HAVE_TUN_PI) && defined(HAVE_IPHDR) && defined(HAVE_IOVEC) && defined(ETH_P_IPV6) && defined(ETH_P_IP) && defined(HAVE_READV) && defined(HAVE_WRITEV)
-#define LINUX_IPV6 1
-/* #warning IPv6 ON */
-#else
-#define LINUX_IPV6 0
-/* #warning IPv6 OFF */
-#endif
-
 #if !PEDANTIC
 
 void
@@ -1388,13 +1380,6 @@ open_tun (const char *dev, const char *dev_type, const char *dev_node, struct tu
 {
   struct ifreq ifr;
 
-  /* warn if a very old linux version is used & --tun-ipv6 set
-   */
-#if LINUX_IPV6 == 0
-  if ( tt->ipv6 )
-    msg (M_WARN, "NOTE: explicit support for IPv6 tun devices is not provided for this OS");
-#endif
-
   /*
    * We handle --dev null specially, we do not open /dev/null for this.
    */
@@ -1623,7 +1608,6 @@ close_tun (struct tuntap *tt)
 int
 write_tun (struct tuntap* tt, uint8_t *buf, int len)
 {
-#if LINUX_IPV6
   if (tt->ipv6)
     {
       struct tun_pi pi;
@@ -1649,14 +1633,12 @@ write_tun (struct tuntap* tt, uint8_t *buf, int len)
       return(ret - sizeof(pi));
     }
   else
-#endif
     return write (tt->fd, buf, len);
 }
 
 int
 read_tun (struct tuntap* tt, uint8_t *buf, int len)
 {
-#if LINUX_IPV6
   if (tt->ipv6)
     {
       struct iovec vect[2];
@@ -1672,7 +1654,6 @@ read_tun (struct tuntap* tt, uint8_t *buf, int len)
       return(ret - sizeof(pi));
     }
   else
-#endif
     return read (tt->fd, buf, len);
 }