Common SSH Tips and Info

If you deleted the "@internal1" key from your profile

As long as you have at least one public key configured in your profile, use your SSH client to connect to gw.orbit-lab.org and run the following commands there. You do not need to make a reservation in the scheduler for this.

rm ~/.ssh/id_rsa
rm ~/.ssh/id_rsa.pub
ssh-keygen -t rsa -C "@internal1"

Press 'Enter' at every prompt so that the default filename (id_rsa) and no password is used.

Then type the following command:

cat ~/.ssh/id_rsa.pub >> ~/.ssh/authorized_keys

The internal key should now be restored.

Prevent unknown host key error when connecting to node

Configure you ssh client not to use strict host key checking

For openssh, this is -o StrictHostKeyChecking=no or the same in the .config file

Using a .config file for SSH (Linux, Mac, and WSL ONLY)

We'd like to do a few things for convenience:

1. log into nodes as root by default
2. allow forwarding of X11 applications
3. Suppress annoying host key warnings

First, log into any console, or gw.orbit-lab.org

After logging in, create or modify the file at ~/.ssh/config

Add the following to the file

Host sdr?-md* sdr?-s?-lg* srv?-co* srv?-lg* node?-* node??-*
  User root
  UserKnownHostsFile /dev/null
  StrictHostKeyChecking no
  ForwardX11 yes

• Host: The Host line matches common naming conventions for nodes within the testbed
• User: root is set to match the common default for baseline
• UserKnownHostsFile: is set to /dev/null to prevent saving new host keys for nodes
• StrictHostKeyChecking: disables the warning message. SSH complains when host keys for a dns name change. This is a useful security feature, but is inconvenient within the testbed, where the operating system on a trusted machine changes frequently. Do not set it as a wildcard default for public endpoints, or you will be vulnerable to spoofing or man in the middle attacks.
• ForwardX11: allows the forwarding of graphical applications running the X11 protocol from a node back to your machine