Core Shell/ Tunnel vs. SSH Shell/ Tunnel

OpenSSH is the de facto standard implementation of the SSH protocol, compared to OpenSSH, SSH Shell and SSH Tunnel lack tons of advanced features including, but not limited to, agent forwarding, certificates, proxy jump, post command, incompatible with some kinds of devices like Cisco routers…

SSH Shell and SSH Tunnel are based on an open source library –– libssh. But unfortunately it is not fully compatible with OpenSSH, lacks lots of advanced features. We worked day and night to try to make it as functional as OpenSSH: we submitted patches, created an open source framework SSHKitCore to overcome libssh congenital defects, invested a lot of time and energy.

We’ve improved libssh to some extent, but still far from as powerful as OpenSSH. So we made a bold decision: start from scratch, drop libssh-based infrastructure, embrace the stable and full-featured OpenSSH and try to deep integrate with it. We named these brand new apps Core Shell and Core Tunnel.

And other underlying technologies also have been dramatically changed. Take the example of Sync. Sync is hard, SSH Shell and SSH Tunnel are using plain text to store host configurations, it is inefficient and almost impossible to solve sync merge conflicts. On the other hand, Core Shell and Core Tunnel are synchronizable from the first day.

Although Core Shell/ Tunnel and SSH Shell/ Tunnel share similar names and user interface, but they are essentially different.

Advantages of Core Shell and Core Tunnel

1. Completely compatible with OpenSSH

We’ve employed Apple’s XPC technology to turn the standard OpenSSH into a XPC service. So theoretically, Core Shell and Core Tunnel can be nearly 100% compatible with OpenSSH.

2. Even more secure and stable

XPC is widely used by Apple itself, e.g. Safari, Xcode, App Store and other system services. By using XPC technology, Core Shell and Core Tunnel are more secure than invoke OpenSSH as subprocess.

Furthermore, an OpenSSH XPC service instance crash won’t affect other instances or the app, Core Shell and Core Tunnel are super stable over SSH Shell and SSH Tunnel .

3. 3x faster on transfer rates

Our benchmark results under exact same environment:

Application Download Speed (MB/s)
Core Tunnel 140
SSH Tunnel 48
Application Upload Speed (MB/s)
Core Tunnel 130
SSH Tunnel 29

4. Sync

Core Shell and Core Tunnel support two sync options:

  • iCloud: Host configuration changes will automatically sync on all your Macs with iCloud, just make sure they are signed in to the same iCloud account.

  • Folder: Choose this option if you want syncing to a local, removable drive (external hard drive or USB stick), even to a folder on a network volume (Time Capsule or other NAS).