peerko

NAT Traversal hole punching P2P chat application

Introduction

peerko is a P2P chat application utilizing a popular NAT traversal technique called hole punching. Control and chat messages are transported using a custom protocol over UDP.

peerko runs in two modes:

server - runs a rendezvous server for peer discovery
client - known as chat, runs a client with a terminal UI that enables exchanging messages with other peers

Usage

To run the P2P chat, some conditions need to be fulfilled:

ONE server with a public IP address should be running in server mode (-s true); messages are not relayed through this server, it only acts as a rendezvous server to exchange public interfaces over peers
NAT types in front of the chat peers should be endpoint independent

Chat peers don't need to have a static, public IP address.

Running the server binary:

peerko --name my-server --group chatting --port 8000 -s true

Running the client binary:

peerko --name my-client-app --group chatting --port 8000 -b SERVER_IP:8000

Running in Docker:

docker run -it --rm -p 8000:8000 penumbra23/peerko:latest --name my-server --group chatting --port 8000 -s true

Commands

When running the chat client, besides sending messages there are additional helper commands:

peers - list connected peers
req - send a MemberRequest to connected peers to discover additional peers

NOTE: if you don't see the neighbour peers, send a req command to get the list of peers from known peers

Contribution

If you want to contribute to this project, there are some additional features to be made:

automatic peer discovery (periodically send MemberRequest)
message encryption
logging

License

MIT