Add VTI IPsec warning (1.3)

1 files changed, 18 insertions, 1 deletions

diff --git a/docs/configuration/interfaces/vti.rst b/docs/configuration/interfaces/vti.rst
index 34842866..1704b9d1 100644
--- a/docs/configuration/interfaces/vti.rst
+++ b/docs/configuration/interfaces/vti.rst
@@ -20,4 +20,21 @@ Results in:
       address 192.168.2.249/30
       address 2001:db8:2::249/64
       description "Description"
-  }
\ No newline at end of file
+  }
+
+.. warning:: When using site-to-site IPsec with VTI interfaces,
+   be sure to disable route autoinstall
+
+.. code-block:: none
+  
+  set vpn ipsec options disable-route-autoinstall
+
+More details about the IPsec and VTI issue and option disable-route-autoinstall
+https://blog.vyos.io/vyos-1-dot-2-0-development-news-in-july
+
+The root cause of the problem is that for VTI tunnels to work, their traffic 
+selectors have to be set to 0.0.0.0/0 for traffic to match the tunnel, even 
+though actual routing decision is made according to netfilter marks. Unless 
+route insertion is disabled entirely, StrongSWAN thus mistakenly inserts a 
+default route through the VTI peer address, which makes all traffic routed 
+to nowhere.
\ No newline at end of file