Step 1 Input ACLs configured on the inbound interface are checked.
Step 2 Unicast RPF checks to see if the packet has arrived on the best return path to the source, which it does by doing a reverse lookup in the FIB table.
Step 3 CEF table (FIB) lookup is carried out for packet forwarding.
Step 4 Output ACLs are checked on the outbound interface.
Step 5 The packet is forwarded.