Setting Up the Secure GRE or DVMRP Connection

In Figure 29, a secure GRE/IPSec connection is set up between two E-series routers. To set up the secure connection:

Set up the IPSec connection between the two routers. IKE signals a security association (SA) between the two IPSec tunnel endpoints.
Two unidirectional SAs are established to secure data traffic.
Set up a GRE tunnel between the two routers.

The GRE tunnel now runs over the SAs that IKE established.

Figure 29: GRE/IPSec Connection

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