HP 5920 Series Configuration Manual page 366

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