What is Reverse Route Injection?
Routing is a critical part of almost every IPsec VPN deployment. Be certain that your encryption devices such as Routers and PIX or ASA Security Appliances have the proper routing information to send traffic over your VPN tunnel.
Moreover, if other routers exist behind your gateway device, be sure that those routers know how to reach the tunnel and what networks are on the other side.
Reverse Route Injection is used to learn routes without the use of dynamic routing protocols like EIGRP, OSPF or RIP, the problem with dynamic routing protocols are - you not always want to expose our whole infrastructure by sharing our routing updates or different parties use different routing protocols.
Core issue
Reverse Route Injection (RRI) provides a scaleable mechanism to dynamically learn and advertise the IP address and subnets that belong to a remote site that connects through an IPSec VPN tunnel.
Resolution
For information on configuring RRI, refer these documents:
Problem Type
How to (General Information)
Product Family
Firewall - IOS firewall
Features & Tasks
Reverse route injection