This will give you a proxy to domain.com:
All data sent from your client will be logged in client.txt
All data received from the server will be logged in server.txt
mkfifo buffer; while true; do cat buffer | nc -lp 80 | tee -a client.txt | nc domain.com 80 | tee buffer >> server.txt ; done
Now you can connect to domain.com through http://127.0.0.1
Todo:
* handle more then 1 connect simultaneously.
Currently, you have to set network.http.max-connections in Firefox to one, so Firefox only sends one request at a time.