< ~wiki

ssh

or, how to tell other computers to do cool things


all users are required to use an ssh keypair for login, or will be required to proceed with manual account recovery with ~ben or another admin. drop a line to sudoers@tilde.team or hop on irc for assistance.

tilde.team details

ports 22, 80, 443, and 2222 are available for ssh.

the primary ip has 80 and 443 in use by nginx.

use ssh.tilde.team to reach the secondary ip and use 80 and 443 for ssh.

so, for example, you can do:

ssh -p 443 user@ssh.tilde.team
ssh user@tilde.team  # this uses port 22, which can be blocked on some networks

intro

if you just want to get right to a tutorial you can skip over this background info

while tilde.team is accessible on the web and features lovely web pages written by its users, most interaction with tilde.team takes place inside the machine that runs tilde.team as opposed to via web forms that have an effect from outside tilde.team's computer.

this is what sets tilde.team apart from most other online communities. you connect directly to another computer from yours alongside other people and then write your web pages, chat, and play games all via text-based interfaces right on tilde.team's computer.

prior to the web (which debuted in 1995) this is how pretty much all computer stuff got done. you connected directly to a machine (usually over a direct, physical phone line) and did your work there.

for a long time, people used a tool called telnet to connect to other computers. these days we use a tool called ssh.

ssh is a text-based tool that provides a direct connection from your computer to another. ssh is an acronym that stands for secure shell. the shell part refers to the fact that it's a text-based tool; we use the word shell to refer to a text-based interface that you give commands to. the secure part refers to the fact that, when you're using ssh, no one can spy on your connection to another computer (unlike the old telnet command).

why bother with all of this? passwords are really insecure and hard to manage. using keys makes life easier for you, fair user (your account is less likely to be hacked) and for me, your humble sysadmin (less administration than passwords).


how to make an ssh key

SSH supports a handful of types of cryptographic keys. The most used are RSA and the more modern Ed25519.

RSA is the de-facto standard and is supported everywhere (just choose a big enough key like 4096 bits to be secure). Ed25519 is designed to be faster and smaller withouth sacrificing security, so is best suited for embedded devices or machines with low resources. It's supported on tilde (and really on any modern system) but you may find older systems which do not support it.

Below you'll find instructions to generate either type (or both if you want).

Keep in mind that these instructions leave your private keys unencrypted in your local hard disk. So keep them private; never share them. A good solution is to provide a password for them at creation time, but this implies entering a password any time you used them (impractical) or use something like ssh-agent (a bit more complex)

We don't have documentation for this (yet) so either go with no password keys, or ask on IRC (#team) for help.

pick your fighter: [mac] | [windows] | [linux]


mac

generating your keypair

  1. open terminal (it's in /Applications/Utilities)

  2. create your .ssh directory:

mkdir -m 700 ~/.ssh
  1. create your keys:

for rsa keys:

ssh-keygen -t rsa -b 4096

for dd25519 keys:

ssh-keygen -t ed25519 -a 100
  1. if you press enter to accept the defaults, your public and private key will be located at ~/.ssh/id_rsa.pub and ~/.ssh/id_rsa respectively (or ~/.ssh/id_ed25519.pub and ~/.ssh/id_ed25519 if you chose ed25519 type)

  2. cat ~/.ssh/id_rsa.pub (or cat ~/.ssh/id_ed25519.pub for ed25519)

  3. copy the output of the last command and paste it in the sshkey field on the signup form (or email it to ~sudoers if you already have an account)

using your keypair

once ~ben or another admin approves your signup, you can join the tilde.team

  1. open terminal (it's in /Applications/Utilities)

  2. ssh to tilde.team:

ssh username@tilde.team

where username is your username (~ben would use ssh ben@tilde.team)

  1. profit???

windows

there are a couple options for using ssh on windows these days. i like to use git bash.

generating your keypair

choose from any of the following options:

  1. open your new shell

  2. create your .ssh directory

mkdir .ssh
  1. create your keypair

for rsa keys:

ssh-keygen -t rsa -b 4096

for ed25519 keys:

ssh-keygen -t ed25519 -a 100
  1. if you press enter to accept the defaults, your public and private key will be located at ~/.ssh/id_rsa.pub and ~/.ssh/id_rsa respectively (or ~/.ssh/id_ed25519.pub and ~/.ssh/id_ed25519 if you chose ed25519 type)

  2. cat ~/.ssh/id_rsa.pub (or cat ~/.ssh/id_ed25519.pub for ed25519)

  3. copy the output of the last command and paste it in the sshkey field on the signup form (or email it to ~sudoers if you already have an account)

using your keypair

once ~ben or another admin approves your signup, you can join the tilde.team

  1. open terminal (it's in /Applications/Utilities)

  2. ssh to tilde.team:

ssh username@tilde.team

where username is your username (~ben would use ssh ben@tilde.team)

  1. profit???

linux

there are a lot of linux distros, but ssh and ssh-keygen should be available in almost all cases. if they're not, look up how to install ssh for your distro.

generating your keypair

  1. make sure you have a ~/.ssh directory
mkdir -m 700 ~/.ssh
  1. create your keys

for rsa keys:

ssh-keygen -t rsa -b 4096

for ed25519 keys:

ssh-keygen -t ed25519 -a 100
  1. if you press enter to accept the defaults, your public and private key will be located at ~/.ssh/id_rsa.pub and ~/.ssh/id_rsa respectively (or ~/.ssh/id_ed25519.pub and ~/.ssh/id_ed25519 if you chose ed25519 type)

  2. cat ~/.ssh/id_rsa.pub (or cat ~/.ssh/id_ed25519.pub for ed25519)

  3. copy the output of the last command and paste it in the sshkey field on the signup form (or email it to sudoers@tilde.team if you already have an account)

using your keypair

once ~ben or another admin approves your signup, you can join the tilde.team

  1. open a terminal (this depends on your distro)

  2. ssh to tilde.team:

ssh username@tilde.team

where username is your username (~ben would use ssh ben@tilde.team)

  1. profit???

this tutorial is based on and uses parts of the tilde.club ssh primer and the tilde.town ssh guide.


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