Spoof source IP address in ICMP ECHO REQUEST packet

Question

I get two wireless devices A and B, and an AP. The IP address of A is 1.2.3.4 and that of B is 1.2.3.5. If A send an ICMP ECHO REQUEST packet to the AP, in which the source IP address is spoofed to 1.2.3.5, will B receive an ICMP ECHO REPLY from the AP?

My program worked fine when the IP address was not spoofed. The ECHO REPLY packet can be received by the same device that send the ECHO REQUEST. But when I send an spoofed packet, nothing received in the other device.

Can the process be achieved? If yes, what should I do to receive the ECHO REPLY from the AP?

Answer 1

Some access points (eg the Hotspot service in my Android phone) do not even forward packets between connected wireless devices. In other words, routing to the WAN link is enabled but communication between the WLAN devices is disabled. The WLAN devices cannot successfully ping or connect to each other. When using some other access points they can, so verify the forwarding by testing your access point. The problem you have might be outside your software.