Why did I get a Null/Loopback after I send a packet with pcpp?

Asked May 16 '23 at 11:06

Active May 16 '23 at 11:06

Viewed 42 times

I have a nginx instance running on localhost:80 and I want to send it a raw TCP SYN packet.

So I generate a dummy packet and send it to lo interface via pcapplusplus. However, when the Wireshark is monitoring the lo, it says this packet is Null/Loopback and did not do more things, it seems. But if I write this packet to a pcap file, Wireshark can recognize it well. Two packet data is 100% same.

I'm a bit confused and what is the best practice to accomplish my needs?

asked May 16 '23 at 11:06

Junhui Zhu

What operating system is this on? – user16139739 May 19 '23 at 20:40
Ubuntu server 22 – Junhui Zhu May 20 '23 at 03:12
Where did Wireshark say that the packet is Null/Loopback? On Linux, loopback device packets have *Ethernet* headers, not *BSD loopback* headers (which is what "Null/Loopback" refers to). – user16139739 May 25 '23 at 22:22

Why did I get a Null/Loopback after I send a packet with pcpp?

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