l4p

Hey, now we are on level 4!

l4p is a layer 4 proxy implemented by Rust to listen on specific ports and transfer TCP data to remote addresses (only TCP) according to the configuration.

Features

• Listen on specific port and proxy to local or remote port
• SNI-based rule without terminating TLS connection
• DNS-based backend with periodic resolution

Installation

To gain best performance on your computer's architecture, please consider build the source code. First, you may need Rust tool chain.

$ cd l4p
$ cargo build --release

Binary file will be generated at target/release/l4p, or you can use cargo install --path . to install.

Or you can use Cargo to install l4p:

$ cargo install l4p

Or you can download binary file form the Release page.

Configuration

l4p will read yaml format configuration file from /etc/l4p/l4p.yaml, and you can set custom path to environment variable L4P_CONFIG, here is an minimal viable example:

version: 1
log: info

servers:
  proxy_server:
    listen:
      - "127.0.0.1:8081"
    default: remote

upstream:
  remote: "tcp://www.remote.example.com:8082" # proxy to remote address

There are two upstreams built in:

• Ban, which terminates the connection immediately
• Echo, which reflects back with the input

For detailed configuration, check this example.

Thanks

• fourth, of which this is a heavily modified fork.

License

l4p is available under terms of Apache-2.0.