TCPPrism

Mirrors TCP traffic between a client and a forward host, but also sends the same traffic to a mirror host. The response from the mirror is thrown away.

Installation

From source:

git clone https://github.com/84codes/tcpprism.git
cd tcpprism
shards build --release --production
install bin/tcpprism /usr/local/bin/

Or download precompiled binaries.

Usage

Usage: tcpprism [arguments]
    -l, --listen=ADDR                Address and port to listen on (required)
    -f, --forward=ADDR               Address and port to forward traffic to (required)
    -m, --mirror=ADDR                Address and port to mirror traffic to (required)
    -h, --help                       Show this help

If you for example would like to mirror the traffic currently coming in to a server on port 80, to another server also running on port 80, but without stopping and changing port of the original server, you can use trick with iptables that redirects port 80 to the tcpprism server, which in turn will forward the traffic to both the original server and the server on the other host.

ulimit -n 16384
iptables -t nat -A PREROUTING -i ens5 -p tcp --dport 80 -j REDIRECT --to-port 8080
tcpprism --listen 0.0.0.0:8080 --forward 127.0.0.1:80 --mirror 10.0.0.2:80

Contributing

1. Fork it (https://github.com/84codes/tcpprism/fork)
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create a new Pull Request

Contributors

• Carl Hörberg - creator and maintainer