RSA Keys: Added information related to RSA keys

RSA-Keys page was blank, so added the steps to generate and add the keys to
the VPN IPSec config.
Also corrected the IPSec/GRE page where authentication parameter was
missing before remote-id.

1 files changed, 85 insertions, 1 deletions

diff --git a/docs/configuration/vpn/rsa-keys.rst b/docs/configuration/vpn/rsa-keys.rst
index 9f289d0d..7912cffe 100644
--- a/docs/configuration/vpn/rsa-keys.rst
+++ b/docs/configuration/vpn/rsa-keys.rst
@@ -1,4 +1,88 @@
 
 ########
 RSA-Keys
-########
\ No newline at end of file
+########
+RSA can be used for services such as key exchanges and for encryption purposes.
+To make IPSec work with dynamic address on one/both sides, we will have to use
+RSA keys for authentication. They are very fast and easy to setup.
+
+First, on both routers run the operational command “generate vpn rsa-key 
+bits 2048”. You may choose different length than 2048 of course.
+
+.. code-block:: none
+
+  vyos@left# run generate vpn rsa-key bits 2048
+  Generating rsa-key to /config/ipsec.d/rsa-keys/localhost.key
+
+  Your new local RSA key has been generated
+  The public portion of the key is:
+
+  0sAQO2335[long string here]
+
+Please note down this public key, as you have to add this RSA key in the opposite router.
+
+.. code-block:: none
+
+  set vpn rsa-keys rsa-key-name LEFT rsa-key KEYGOESHERE
+
+Now you are ready to setup IPsec. The key points:
+
+1. Since both routers do not know their effective public addresses, we set the local-address of the peer to "any".
+2. On the initiator, we set the peer address to its public address, but on the responder we only set the id.
+3. On the initiator, we need to set the remote-id option so that it can identify IKE traffic from the responder correctly.
+4. On the responder, we need to set the local id so that initiator can know who's talking to it for the point #3 to work.
+5. Don't forget to enable NAT traversal on both sides, "set vpn ipsec nat-traversal enable".
+
+LEFT SIDE:
+
+.. code-block:: none
+
+  set vpn rsa-keys rsa-key-name RIGHT rsa-key <PUBLIC KEY FROM THE RIGHT>
+
+  set vpn ipsec ipsec-interfaces interface eth0
+  set vpn ipsec nat-traversal 'enable'
+
+  set vpn ipsec esp-group MyESPGroup proposal 1 encryption aes128
+  set vpn ipsec esp-group MyESPGroup proposal 1 hash sha1
+
+  set vpn ipsec ike-group MyIKEGroup proposal 1 dh-group 2
+  set vpn ipsec ike-group MyIKEGroup proposal 1 encryption aes128
+  set vpn ipsec ike-group MyIKEGroup proposal 1 hash sha1
+
+  set vpn ipsec site-to-site peer 192.0.2.60 authentication mode rsa
+  set vpn ipsec site-to-site peer 192.0.2.60 authentication id @LEFT
+  set vpn ipsec site-to-site peer 192.0.2.60 authentication rsa-key-name RIGHT
+  set vpn ipsec site-to-site peer 192.0.2.60 authentication remote-id RIGHT
+  set vpn ipsec site-to-site peer 192.0.2.60 default-esp-group MyESPGroup
+  set vpn ipsec site-to-site peer 192.0.2.60 ike-group MyIKEGroup
+  set vpn ipsec site-to-site peer 192.0.2.60 local-address any
+  set vpn ipsec site-to-site peer 192.0.2.60 connection-type initiate
+  set vpn ipsec site-to-site peer 192.0.2.60 tunnel 1 local prefix 192.168.99.1/32
+  set vpn ipsec site-to-site peer 192.0.2.60 tunnel 1 remote prefix 192.168.99.2/32
+
+RIGHT SIDE:
+
+.. code-block:: none
+
+  set vpn rsa-keys rsa-key-name LEFT rsa-key <PUBLIC KEY FROM THE LEFT>
+
+  set vpn ipsec ipsec-interfaces interface eth0
+  set vpn ipsec nat-traversal 'enable'
+
+  set vpn ipsec esp-group MyESPGroup proposal 1 encryption aes128
+  set vpn ipsec esp-group MyESPGroup proposal 1 hash sha1
+
+  set vpn ipsec ike-group MyIKEGroup proposal 1 dh-group 2
+  set vpn ipsec ike-group MyIKEGroup proposal 1 encryption aes128
+  set vpn ipsec ike-group MyIKEGroup proposal 1 hash sha1
+
+  set vpn ipsec site-to-site peer @LEFT authentication id @RIGHT
+  set vpn ipsec site-to-site peer @LEFT authentication mode rsa
+  set vpn ipsec site-to-site peer @LEFT authentication rsa-key-name LEFT
+  set vpn ipsec site-to-site peer @LEFT connection-type respond
+  set vpn ipsec site-to-site peer @LEFT default-esp-group MyESPGroup
+  set vpn ipsec site-to-site peer @LEFT ike-group MyIKEGroup
+  set vpn ipsec site-to-site peer @LEFT local-address any
+  set vpn ipsec site-to-site peer @LEFT tunnel 1 local prefix 192.168.99.2/32
+  set vpn ipsec site-to-site peer @LEFT tunnel 1 remote prefix 192.168.99.1/32
+