Session Report

Summary:

Test run at: 2026-05-28 13:13:11 GMT
Client Prefix (v4): 143.255.249.x/24
Client AS (v4): 61468
IPv4 Probes: 162

Outbound spoofing summary (from the client to our server)
Source address type	IPv4
Private - RFC1918	blocked
Routable	blocked
Largest spoofable neighbor prefix length	none

Spoof status key
received		Spoofed packet was received.	✔	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 (143.255.249.x/24) can spoof 0 neighboring addresses

Spoofed source address (anon)	Prefix Length	ASN of spoofed source address	Received
143.255.249.x/24	/31	61468	sendto
143.255.249.x/24	/30	61468	sendto
143.255.249.x/24	/29	61468	sendto
143.255.249.x/24	/28	61468	sendto
143.255.249.x/24	/27	61468	sendto
143.255.249.x/24	/26	61468	sendto
143.255.249.x/24	/25	61468	sendto
143.255.249.x/24	/24	61468	sendto
143.255.248.x/24	/23	61468	sendto
143.255.251.x/24	/22	61468	sendto
143.255.253.x/24	/21	263405	sendto
143.255.241.x/24	/20	265157	sendto
143.255.233.x/24	/19	28649	sendto
143.255.217.x/24	/18	52935	sendto
143.255.185.x/24	/17	262587	sendto
143.255.121.x/24	/16	61948	sendto
143.254.249.x/24	/15	3734	sendto
143.253.249.x/24	/14	16509	sendto
143.251.249.x/24	/13	UNROUTED	sendto
143.247.249.x/24	/12	UNROUTED	sendto
143.239.249.x/24	/11	1213	sendto
143.223.249.x/24	/10	UNROUTED	natblock
143.191.249.x/24	/9	16509	sendto
143.127.249.x/24	/8	UNROUTED	sendto

Meaning of status in Received column:

natblock	Spoofed probe packets appear to be blocked by your local NAT or firewall rather than being rewritten with a public source address.
sendto	The spoofer client was unable to send spoofed headers due to an operating system restriction.

IPv4 Outbound Filtering Depth:

The tracefilter test found your host unable to spoof routable, non-adjacent source addresses through even the first IP hop.

Summary:

The results from all tests are aggregated to produce a summary "State of IP Spoofing" report.

Feedback:

We welcome questions and feedback to the Spoofer Information Mailing List and invite users to join the Spoofer Users Mailing List for discussion and announcements.