When the number of static IP addresses in an organization is limited, the ISP allocates temporary IP addresses to computers wishing to communicate over IP. These temporary addresses are called dynamic IP addresses.
The Branch Gateway IPSec VPN feature provides dynamic local peer IP address support. To work with dynamic local peer IP, you must first configure some prerequisites and then instruct the Branch Gateway to learn the IP address dynamically using either PPPoE or DHCP client.
Note:
When working with dynamic local peer IP, you must verify that it is the Branch Gateway that initiates the VPN connection. The VPN peer cannot initiate the connection since it does not know the Branch Gateway’s IP address. To maintain the Branch Gateway as the initiator, do one of the following:
Specify continuous channel in the context of the VPN peer, to maintain the IKE phase 1 connection even when no traffic is sent (see Continuous channel).
Maintain a steady transmission of traffic by sending GRE keepalives or employing object tracking.
