I have a couple of questions about peer configuration.

The peers do not have to match end to end on VPN config?

I am looking at a scenario that has the main site configured to peer to the remote site's backup wireless router. The wireless router is facing the Internet, so the Main site has it's peer set to a Public Internet address.

The remote site is configured with a default route to the Wireless router, if the main mpls connection drops, all traffic is sent to the wireless router, then to the Internet.

The remote site route has a loopback interface 172.16.0.9.

A partial config is shown below, my questions are concnering the:

crypto isakmp key xxxx address 172.16.0.9

Why is this here if it is the loopback address of the router that owns this loopback?

crypto map PEFCU_Crypt local-address Loopback0

What is this line doing?

Thanks

crypto isakmp policy 10

encr 3des

hash md5

authentication pre-share

crypto isakmp key xxxx address 172.16.0.1

crypto isakmp key xxxx address 172.16.0.9

!

!

crypto ipsec transform-set 1234 esp-3des esp-md5-hmac

!

crypto map PEFCU_Crypt local-address Loopback0

crypto map PEFCU_Crypt 10 ipsec-isakmp

set peer 172.16.0.1

set transform-set 1234

match address 10

qos pre-classify