trudy | transparent proxy that can modify and drop traffic | Proxy library

Configure a virtual machine (Trudy has been tested on a 64-bit Debian 8 VM) to shove all traffic through Trudy. I personally use a Vagrant VM that sets this up for me. The Vagrant VM is available here. If you would like to use different --to-ports values, you can use Trudy's command line flags to change Trudy's listening ports. Clone the repo on the virtual machine and build the Trudy binary. Run the Trudy binary as root. This starts the listeners. If you ran the iptables commands above, iptables will forward traffic destined for port 443 to port 6443. Trudy listens on this port and expects traffic coming into this port to be TLS. All other TCP connections will be forwarded through port 6666. Setup your host machine to use the virtual machine as its router. You should see connections being made in Trudy's console but not notice any traffic issues on the host machine (except TLS errors).
Configure a virtual machine (Trudy has been tested on a 64-bit Debian 8 VM) to shove all traffic through Trudy. I personally use a Vagrant VM that sets this up for me. The Vagrant VM is available here. If you would like to use different --to-ports values, you can use Trudy's command line flags to change Trudy's listening ports. iptables -t nat -A PREROUTING -i eth1 -p tcp --dport 8888 -m tcp -j REDIRECT --to-ports 8080 iptables -t nat -A PREROUTING -i eth1 -p tcp --dport 443 -m tcp -j REDIRECT --to-ports 6443 iptables -t nat -A PREROUTING -i eth1 -p tcp -m tcp -j REDIRECT --to-ports 6666 ip route del 0/0 route add default gw 192.168.1.1 dev eth1 sysctl -w net.ipv4.ip_forward=1
Clone the repo on the virtual machine and build the Trudy binary. git clone https://github.com/kelbyludwig/trudy.git cd trudy go install
Run the Trudy binary as root. This starts the listeners. If you ran the iptables commands above, iptables will forward traffic destined for port 443 to port 6443. Trudy listens on this port and expects traffic coming into this port to be TLS. All other TCP connections will be forwarded through port 6666. sudo $GOPATH/bin/trudy
Setup your host machine to use the virtual machine as its router. You should see connections being made in Trudy's console but not notice any traffic issues on the host machine (except TLS errors).
In order to manipulate data, just implement whatever functions you might need within the module package. The default implementations for these functions are hands-off, so if they do not make sense for your situation, feel free to leave them as they are. More detailed documentation is in the module package and the data flow is detailed below.
To access the interceptor, visit http://<IP ADDRESS OF VM>:8888/ in your web browser. The only gotcha here is you must visit the interceptor after starting Trudy but before Trudy receives a packet that it wants to intercept.