SSH proxy jump
As the collective sandbox servers are hosted from the school, they use a hidden VPN network to connect to the internet, famously known as the HUB.
To be able to SSH to a sandbox server from outside of the school, you can use a SSH proxy jump.
The SSH proxy jump will make a connection to the sandbox through XPUB's XVM server.
Using a SSH proxy jump to access a sandbox server
Download the jump key files from Zulip and save them to the ~/.ssh/ on your laptop (not on chopchop!):
jump jump.pub
Copy the following config file, change the USERNAME to your username, and save it to ~/.ssh/config on your laptop:
Host xvm_jump User jump Hostname 194.61.65.6 Port 2501 Identityfile ~/.ssh/jump Host chopchop Hostname 10.0.0.16 User USERNAME ProxyJump xvm_jump Identityfile ~/.ssh/id_ed25519
Now, you should be able to ssh to chopchop, both from the school and outside the school, with this command:
$ ssh chopchop