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Example: AS PIC IKE Dynamic SA Configuration

Figure 1: AS PIC IKE Dynamic SA Topology DiagramAS PIC IKE Dynamic SA Topology Diagram

Figure 1 shows the same IPSec topology as seen in the AS PIC manual SA example. However, this configuration requires Routers 2 and 3 to establish an IPSec tunnel using an IKE dynamic SA, enhanced authentication, and stronger encryption. Routers 1 and 4 continue to provide basic connectivity and are used to verify that the IPSec tunnel is operational.

Note:

When you do not specify an IKE proposal, an IPSec proposal, and an IPSec policy on an AS PIC, the Junos OS defaults to the highest level of encryption and authentication. As a result, the default authentication protocol is ESP, the default authentication mode is HMAC-SHA1-96, and the default encryption mode is 3DES-CBC. For more information about default IKE and IPSec policies and proposals on the AS PIC, see Configuring IKE Dynamic SAs.

On Router 1, provide basic OSPF connectivity to Router 2.

Router 1

On Router 2, enable OSPF as the underlying routing protocol to connect to Routers 1 and 3. Configure a bidirectional IKE dynamic SA in a rule called rule-ike at the [edit ipsec-vpn rule] hierarchy level. Reference this rule in a service set called service-set-dynamic-BiEspsha3des at the [edit services service-set] hierarchy level.

Using default values in the AS PIC, you do not need to specify an IPsec proposal, IPsec policy, or IKE proposal. However, you do need to configure a preshared key in an IKE policy with the pre-shared-key statement at the [edit services ipsec-vpn ike policy policy-name] hierarchy level. (For more information about default IKE and IPsec policies and proposals on the AS PIC, see Configuring IKE Dynamic SAs.)

To direct traffic into the AS PIC and the IPSec tunnel, configure a next-hop style service set and add the adaptive services logical interface used as the IPSec inside interface into the OSPF configuration.

Router 2

On Router 3, enable OSPF as the underlying routing protocol to connect to Routers 2 and 4. Configure a bidirectional IKE dynamic SA in a rule called rule-ike at the [edit ipsec-vpn rule] hierarchy level. Reference this rule in a service set called service-set-dynamic-BiEspsha3des at the [edit services service-set] hierarchy level.

Again, use the same default policies and proposals that you used on Router 2. However, remember to configure a preshared key in an IKE policy with the pre-shared-key statement at the [edit services ipsec-vpn ike policy policy-name] hierarchy level. The key must match the one you specified on Router 2. (For more information about default IKE and IPSec policies and proposals on the AS PIC, see Configuring IKE Dynamic SAs.)

To direct traffic into the AS PIC and the IPSec tunnel, configure a next-hop style service set and add the adaptive services logical interface used as the IPSec inside interface into the OSPF configuration.

Router 3

On Router 4, provide basic OSPF connectivity to Router 3.

Router 4

Verifying Your Work

To verify proper operation of an IKE-based dynamic SA on the AS PIC, use the following commands:

  • ping

  • show services ipsec-vpn ike security-associations (detail)

  • show services ipsec-vpn ipsec security-associations (detail)

  • show services ipsec-vpn ipsec statistics

  • traceroute

The following sections show the output of these commands used with the configuration example:

Router 1

On Router 1, issue a ping command to the so-0/0/0 interface on Router 4 to send traffic across the IPSec tunnel.

Router 2

To verify that the IKE SA negotiation is successful, issue the show services ipsec-vpn ike security-associations command.

To verify that the IPsec security association is active, issue the show services ipsec-vpn ipsec security-associations detail command. Notice that the SA contains the default settings inherent in the AS PIC, such as ESP for the protocol and HMAC-SHA1-96 for the authentication algorithm.

To verify that traffic is traveling over the bidirectional IPSec tunnel, issue the show services ipsec-vpn statistics command:

Bad headers: 0, Bad trailers: 0

Router 3

To verify that the IKE SA negotiation is successful, issue the show services ipsec-vpn ike security-associations command. To be successful, the SA on Router 3 must contain the same settings you specified on Router 2.

To verify that the IPsec SA is active, issue the show services ipsec-vpn ipsec security-associations detail command. To be successful, the SA on Router 3 must contain the same settings you specified on Router 2.

To verify that traffic is traveling over the bidirectional IPsec tunnel, issue the show services ipsec-vpn statistics command:

Bad headers: 0, Bad trailers: 0

Router 4

On Router 4, issue a ping command to the so-0/0/0 interface on Router 1 to send traffic across the IPsec tunnel.

The final way you can confirm that traffic travels over the IPsec tunnel is by issuing the traceroute command to the so-0/0/0 interface on Router 1. Notice that the physical interface between Routers 2 and 3 is not referenced in the path; traffic enters the IPSec tunnel through the adaptive services IPSec inside interface on Router 3, passes through the loopback interface on Router 2, and ends at the so-0/0/0 interface on Router 1.