Pattern of tests from this IP block indicates a switch from allowing spoofing to blocking it.
rewritten
Spoofed packet was received, but the source address was changed en route.
blocked
Spoofed packet was not received, but unspoofed packet was.
unknown
Neither spoofed nor unspoofed packet was received.
IPv4 AS Route:
This test run probed the following paths in order to infer your
ability to send different spoofed source packets. Each node
in the graph corresponds to an autonomous system, i.e.
different Internet service providers. NOTE: This graph does NOT show if
an AS blocks spoofed packets, only the path taken by received spoofed
packets. The IP Path Details
are available for this run. If non-spoofed packets weren't received at
a destination, the traceroute to that destination is not included in this
graph and may even cause a totally empty graph.
IPv4 Adjacent Netblock Testing:
Your host (208.66.128.x/24) can spoof 2047 neighboring addresses (within your /21 prefix)
Spoofed source address (anon)
Prefix Length
ASN of spoofed source address
Received
208.66.128.x/24
/31
16842
yes
208.66.128.x/24
/30
16842
yes
208.66.128.x/24
/29
16842
yes
208.66.128.x/24
/28
16842
yes
208.66.128.x/24
/27
16842
yes
208.66.128.x/24
/26
16842
yes
208.66.128.x/24
/25
16842
yes
208.66.128.x/24
/24
16842
yes
208.66.129.x/24
/23
16842
yes
208.66.130.x/24
/22
16842
yes
208.66.132.x/24
/21
16842
yes
208.66.136.x/24
/20
62947
natblock
208.66.144.x/24
/19
13823
natblock
208.66.160.x/24
/18
10915
natblock
208.66.192.x/24
/17
33724
natblock
208.66.0.x/24
/16
20161
natblock
208.67.128.x/24
/15
30714
natblock
208.64.128.x/24
/14
36069
natblock
208.70.128.x/24
/13
16941
natblock
208.74.128.x/24
/12
6296
natblock
208.82.128.x/24
/11
17185
natblock
208.98.128.x/24
/10
15305
natblock
208.2.128.x/24
/9
1239
natblock
208.194.128.x/24
/8
701
natblock
Meaning of status in Received column:
yes
Packets spoofed from adjacent netblock were received (but that netblock is within the source AS)
natblock
Spoofed probe packets appear to be blocked by your local NAT or firewall rather than being rewritten with a public source address.
IPv4 Outbound Filtering Depth:
The tracefilter test found your host
able to spoof routable, non-adjacent source addresses through the
first 3 IP hop(s).
Summary:
The results from all tests are aggregated to produce a summary
"State of IP Spoofing" report.