Session Report

Summary:

Test run at: 2026-06-17 11:45:33 GMT
Client Prefix (v4): 138.0.55.x/24
Client AS (v4): 264525
IPv4 Probes: 162

Outbound spoofing summary (from the client to our server)
Source address type	IPv4
Private - RFC1918	✔	rewritten
Routable	received
Largest spoofable neighbor prefix length	/25

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.

Warnings:

• ⚠️ Your host is behind a Network Address Translation (NAT) router or firewall but spoofed packets are still being received without modification. See here for more information.

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 (138.0.55.x/24) can spoof 127 neighboring addresses (within your /25 prefix)

Spoofed source address (anon)	Prefix Length	ASN of spoofed source address	Received
138.0.55.x/24	/31	264525	sendto
138.0.55.x/24	/30	264525	sendto
138.0.55.x/24	/29	264525	sendto
138.0.55.x/24	/28	264525	sendto
138.0.55.x/24	/27	264525	sendto
138.0.55.x/24	/26	264525	sendto
138.0.55.x/24	/25	264525	yes
138.0.55.x/24	/24	264525	sendto
138.0.54.x/24	/23	264525	sendto
138.0.53.x/24	/22	264525	sendto
138.0.51.x/24	/21	264542	sendto
138.0.63.x/24	/20	264545	sendto
138.0.39.x/24	/19	264530	sendto
138.0.23.x/24	/18	264528	sendto
138.0.119.x/24	/17	262186	sendto
138.0.183.x/24	/16	28580	sendto
138.1.55.x/24	/15	31898	sendto
138.2.55.x/24	/14	31898	sendto
138.4.55.x/24	/13	766	sendto
138.8.55.x/24	/12	UNROUTED	sendto
138.16.55.x/24	/11	44559	sendto
138.32.55.x/24	/10	18701	sendto
138.64.55.x/24	/9	4685	sendto
138.128.55.x/24	/8	16509	sendto

Meaning of status in Received column:

yes	Packets spoofed from adjacent netblock were received (but that netblock is within the source AS)
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.