HP 3600 v2 Series Security Configuration Manual page 368

Figure 136 URPF work flow
Yes
Does the source
Yes
IP address match
an ARP entry?
No
URPF checks the source address validity:
1.
• Discards packets with a broadcast source address.
Discards packets with an all-zero source address but a non-broadcast destination address. (A
•
packet with source address 0.0.0.0 and destination address 255.255.255.255 might be a DHCP
or BOOTP packet, and is not discarded.)
Check the source
address of the
received packet
A broadcast
source address?
No
An all - zero
source address?
No
Does the FIB
entry match the
source address ?
Yes
Loose URPF?
No
Is the matching
Yes
route a direct
route ?
No
Does the receiving
interface match
the output
interface of the
matching FIB
entry ?
No
357
Yes
Yes
A broadcast
Yes
destination
address ?
No
Is there a default
route ?
Yes
Yes
Loose URPF?
No
Does the output
interface of the
Yes
default route match
the receiving
interface?
Yes
Check passed
No
Discard
No
No