NetFlow is configured on each input interface, then global commands are used to specify the export destination. To ensure a consistant source address address Loopback0 is configured as the export source.

ip cef distributed
ip flow-export version 5 origin-as
ip flow-export destination 10.0.0.100 5004
ip flow-export source Loopback0

interface Loopback0
 ip address 10.1.1.1 255.255.255.255

interface FastEthernet0/1/0
 ip address 10.0.0.1 255.255.255.0
 no ip directed-broadcast
 ip route-cache flow
 ip route-cache distributed

Many other options exist such as aggregated NetFlow and sampled NetFlow which are detailed at (link to URL .