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diff --git a/docs/configuration/vpn/ipsec.rst b/docs/configuration/vpn/ipsec.rst new file mode 100644 index 00000000..38849f67 --- /dev/null +++ b/docs/configuration/vpn/ipsec.rst @@ -0,0 +1,190 @@ +.. _gre-ipsec: + +GRE/IPsec +--------- + +Generic Routing Encapsulation (GRE), GRE/IPsec (or IPIP/IPsec, SIT/IPsec, or any +other stateless tunnel protocol over IPsec) is the usual way to protect the +traffic inside a tunnel. + +An advantage of this scheme is that you get a real interface with its own +address, which makes it easier to setup static routes or use dynamic routing +protocols without having to modify IPsec policies. The other advantage is that +it greatly simplifies router to router communication, which can be tricky with +plain IPsec because the external outgoing address of the router usually doesn't +match the IPsec policy of typical site-to-site setup and you need to add special +configuration for it, or adjust the source address for outgoing traffic of your +applications. GRE/IPsec has no such problem and is completely transparent for +the applications. + +GRE/IPIP/SIT and IPsec are widely accepted standards, which make this scheme +easy to implement between VyOS and virtually any other router. + +For simplicity we'll assume that the protocol is GRE, it's not hard to guess +what needs to be changed to make it work with a different protocol. We assume +that IPsec will use pre-shared secret authentication and will use AES128/SHA1 +for the cipher and hash. Adjust this as necessary. + +.. NOTE:: VMWare users should ensure that VMXNET3 adapters used, e1000 adapters + have known issue with GRE processing + +IPsec policy matching GRE +^^^^^^^^^^^^^^^^^^^^^^^^^ + +The first and arguably cleaner option is to make your IPsec policy match GRE +packets between external addresses of your routers. This is the best option if +both routers have static external addresses. + +Suppose the LEFT router has external address 192.0.2.10 on its eth0 interface, +and the RIGHT router is 203.0.113.45 + +On the LEFT: + +.. code-block:: none + + # GRE tunnel + set interfaces tunnel tun0 encapsulation gre + set interfaces tunnel tun0 local-ip 192.0.2.10 + set interfaces tunnel tun0 remote-ip 203.0.113.45 + set interfaces tunnel tun0 address 10.10.10.1/30 + + ## IPsec + set vpn ipsec ipsec-interfaces interface eth0 + + # IKE group + 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' + + # ESP group + set vpn ipsec esp-group MyESPGroup proposal 1 encryption 'aes128' + set vpn ipsec esp-group MyESPGroup proposal 1 hash 'sha1' + + # IPsec tunnel + set vpn ipsec site-to-site peer 203.0.113.45 authentication mode pre-shared-secret + set vpn ipsec site-to-site peer 203.0.113.45 authentication pre-shared-secret MYSECRETKEY + + set vpn ipsec site-to-site peer 203.0.113.45 ike-group MyIKEGroup + set vpn ipsec site-to-site peer 203.0.113.45 default-esp-group MyESPGroup + + set vpn ipsec site-to-site peer 203.0.113.45 local-address 192.0.2.10 + + # This will match all GRE traffic to the peer + set vpn ipsec site-to-site peer 203.0.113.45 tunnel 1 protocol gre + +On the RIGHT, setup by analogy and swap local and remote addresses. + + +Source tunnel from loopbacks +^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +The scheme above doesn't work when one of the routers has a dynamic external +address though. The classic workaround for this is to setup an address on a +loopback interface and use it as a source address for the GRE tunnel, then setup +an IPsec policy to match those loopback addresses. + +We assume that the LEFT router has static 192.0.2.10 address on eth0, and the +RIGHT router has a dynamic address on eth0. + +**Setting up the GRE tunnel** + +On the LEFT: + +.. code-block:: none + + set interfaces loopback lo address 192.168.99.1/32 + + set interfaces tunnel tun0 encapsulation gre + set interfaces tunnel tun0 address 10.10.10.1/30 + set interfaces tunnel tun0 local-ip 192.168.99.1 + set interfaces tunnel tun0 remote-ip 192.168.99.2 + +On the RIGHT: + +.. code-block:: none + + set interfaces loopback lo address 192.168.99.2/32 + + set interfaces tunnel tun0 encapsulation gre + set interfaces tunnel tun0 address 10.10.10.2/30 + set interfaces tunnel tun0 local-ip 192.168.99.2 + set interfaces tunnel tun0 remote-ip 192.168.99.1 + +**Setting up IPSec** + +However, now you need to make IPsec work with dynamic address on one side. The +tricky part is that pre-shared secret authentication doesn't work with dynamic +address, so we'll have to use RSA keys. + +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] + +Then on the opposite router, add the RSA key to your config. + +.. code-block:: none + + set vpn rsa-keys rsa-key-name LEFT rsa-key KEYGOESHERE + +Now you are ready to setup IPsec. You'll need to use an ID instead of address +for the peer on the dynamic side. + +On the LEFT (static address): + +.. 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 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 @RIGHT authentication mode rsa + set vpn ipsec site-to-site peer @RIGHT authentication rsa-key-name RIGHT + set vpn ipsec site-to-site peer @RIGHT default-esp-group MyESPGroup + set vpn ipsec site-to-site peer @RIGHT ike-group MyIKEGroup + set vpn ipsec site-to-site peer @RIGHT local-address 192.0.2.10 + set vpn ipsec site-to-site peer @RIGHT connection-type respond + set vpn ipsec site-to-site peer @RIGHT tunnel 1 local prefix 192.168.99.1/32 # Additional loopback address on the local + set vpn ipsec site-to-site peer @RIGHT tunnel 1 remote prefix 192.168.99.2/32 # Additional loopback address on the remote + + +On the RIGHT (dynamic address): + +.. 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 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 192.0.2.10 authentication id @RIGHT + set vpn ipsec site-to-site peer 192.0.2.10 authentication mode rsa + set vpn ipsec site-to-site peer 192.0.2.10 authentication rsa-key-name LEFT + set vpn ipsec site-to-site peer 192.0.2.10 remote-id @LEFT + set vpn ipsec site-to-site peer 192.0.2.10 connection-type initiate + set vpn ipsec site-to-site peer 192.0.2.10 default-esp-group MyESPGroup + set vpn ipsec site-to-site peer 192.0.2.10 ike-group MyIKEGroup + set vpn ipsec site-to-site peer 192.0.2.10 local-address any + set vpn ipsec site-to-site peer 192.0.2.10 tunnel 1 local prefix 192.168.99.2/32 # Additional loopback address on the local + set vpn ipsec site-to-site peer 192.0.2.10 tunnel 1 remote prefix 192.168.99.1/32 # Additional loopback address on the remote |