HPN-SSH (High Performance Networking SSH) is a performance-oriented variant of OpenSSH designed to improve data transfer speeds, particularly across high-bandwidth, high-latency networks. It addresses bottlenecks that can prevent conventional SSH connections from making full use of available network capacity.
The software is particularly useful in high-performance computing, research networks and environments where large datasets must be transferred between geographically separated systems. Its optimisations target both network buffering and the cryptographic processing involved in transferring data.
HPN-SSH provides a familiar collection of SSH utilities for remote logins, command execution and file transfers. It remains compatible with standard SSH implementations, allowing organisations to introduce performance improvements without replacing every SSH client and server in their infrastructure.
This is free and open source software.
Key Features
- Optimises application-level receive buffers to match TCP receive buffer sizes, improving throughput over networks with significant latency.
- Multi-threaded AES-CTR encryption distributes cryptographic processing across multiple CPU cores, reducing encryption bottlenecks.
- Parallel ChaCha20-Poly1305 implementation provides improved throughput while maintaining compatibility with conventional SSH implementations.
- Resumable SCP transfers use cryptographic hashes to identify completed data and avoid retransmitting unchanged portions of interrupted transfers.
- Optional Multipath TCP support on Linux allows connections to use multiple network paths where supported by the operating system.
- TCP_INFO metrics provide information about round-trip times, retransmissions, packet loss and transferred data.
- Automatic fallback to the standard SSH port simplifies connections to conventional SSH servers.
- Separate hpn-prefixed executables and configuration paths allow HPN-SSH to coexist with a standard OpenSSH installation.
- Optional NONE cipher operation removes payload encryption after authentication. This is intended only for explicitly trusted environments, as transferred data is no longer confidential.
Website: github.com/rapier1/hpn-ssh
Support:
Developer: Chris Rapier and contributors
License: BSD-style licences
HPN-SSH is written in C. Learn C with our recommended free books and free tutorials.
Related Software
| SSH Servers | |
|---|---|
| OpenSSH | Comprehensive SSH server for secure remote access and file transfers |
| Teleport | Infrastructure access platform with SSH authentication and auditing |
| ssh3 | Faster and rich secure shell using HTTP/3 |
| TinySSH | Minimalistic SSH server |
| Dropbear | Lightweight SSH server for embedded and resource-limited systems |
| quicssh-rs | Simple ssh server |
| ssh2incus | SSH access to Incus instances without running SSH servers inside them |
| Russh | Low-level Tokio SSH2 client and server implementation |
| wolfSSH | Embeddable SSH server implementation with SCP and SFTP support |
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