Route Leakage

Routes can be leaked into OSPF or from OSPF as follows:

Route leakage into OSPF—When another routing protocol adds a new route to the routing table, or when a static route is added to the routing table, OSPF can be informed through the redistribute commands. When OSPF learns the new route, it floods the information into the routing domain by using external LSAs.
Route leakage from OSPF—OSPF adds routing information to the routing table, which is used in forwarding IP packets.