I was trying to create some custom TCP packets using Libnet, but I couldn't figure out how to attach the options using libnet_insert_tcpo(). Whenever I send a SYN packet, I recieve a SYN ACK packet--which is correct. But then my computer automatically sends back a RST packet, even though I never tell it to do this. Does anyone know why? Thanks.

I dont know much about libnet, or about raw sockets, but im going to hazard a guess anyway.

I would say that your TCP stack is recieving the SYN ACK, and it thinks, wait a minute, i didnt initiate a connection, so it replies with RST.

The kernel doesnt think you initiated one because you did it raw, not via its API....

So, you need to somehow recieve the syn ack without the kernel seeing it..

Im probably way off, but was just a suggestion...

Gaz