// HACKER NEWS β CYBERSECURITY
Gonc β Netcat with P2P Nat Traversal
gonc is a Golang-based netcat tool designed to facilitate peer-to-peer communication. Its main features include:
π Automated NAT Traversal: Zero configuration. Both sides only need to agree on a passphrase. By using the -p2p parameter, peers can automatically discover each otherβs network addresses and establish a point-to-point connection through NAT traversal, leveraging public STUN and MQTT services for address exchange.
π End-to-End Encrypted with Mutual Authentication: Supports TLS for TCP and DTLS for UDP encrypted transmission, with passphrase-based mutual identity authentication.
𧩠Flexible Service Configuration: With the -e parameter, you can flexibly set the application to serve each connection. For example, -e /bin/sh can provide a remote cmd shell. You can also use built-in virtual commands for convenient SOCKS5 service, HTTP file service, and traffic forwarding.
can only establish point-to-point connections based on IP and port.
Now, you can also establish point-to-point connections based on a shared passphrase, with automated NAT traversal.
The following diagram shows the process of gonc establishing a P2P connection between a home broadband network (hard NAT) and a peer on a mobile network (symmetric NAT). Since both sides have IPv6, the -4 option is used on both ends to force IPv4 in order to demonstrate NAT traversal.
Both sides agree on the same passphrase.
On the sender side, start an HTTP file server to expose the files or directories to be shared. The -httpserver option accepts multiple paths, each of which can be either a single file or a directory:
After running the following command, all files will be downloaded recursively to the local machine. If the process is interrupted, re-running the command will automatically resume from where it left off:
This option does not start downloading automatically. Instead, you need to manually open a browser and visit http://127.0.0.1:9999 to view the peerβs file list and download files as needed: