440
ï‚¡ If yes, uRPF proceeds to step 3.
ï‚¡ If no, uRPF proceeds to step 6.
3. uRPF checks whether the check mode is loose:
ï‚¡ If yes, uRPF proceeds to step 8.
ï‚¡ If no, uRPF checks whether the matching route is a direct route:
− If yes, uRPF proceeds to step 5.
− If no, uRPF proceeds to step 4.
4. uRPF checks whether the receiving interface matches the output interface of the matching FIB
entry:
ï‚¡ If yes, uRPF proceeds to step 8.
ï‚¡ If no, uRPF proceeds to step 9.
5. uRPF checks whether the source IP address matches an ARP entry:
ï‚¡ If yes, uRPF proceeds to step 8.
ï‚¡ If no, uRPF proceeds to step 9.
6. uRPF checks whether the FIB table has a default route:
ï‚¡ If yes, uRPF proceeds to step 7.
ï‚¡ If no, uRPF proceeds to step 9.
7. uRPF checks whether the check mode is loose:
ï‚¡ If yes, uRPF proceeds to step 8.
ï‚¡ If no, uRPF checks whether the output interface of the default route matches the receiving
interface of the packet:
− If yes, uRPF proceeds to step 8.
− If no, uRPF proceeds to step 9.
8. The packet passes the check and is forwarded.
9. The packet is discarded.
uRPF does not check multicast packets.