SSH.md

SSH

You can read about SSH in the man page, man ssh, and the SSH config man page, man ssh_config.

When you have issues, make sure to use the verbose flag, -v.

Password login

If you don't have any public keys in your user's .ssh folder (i.e. /home/jared/.ssh/), you should be able to login without designating any options:

ssh user@192.168.56.100

But if you do have a few keys, SSH may try those first and you might get a Too many authentication failures error. To fix this, set the PubkeyAuthentication option to no:

ssh -o PubkeyAuthentication=no user@192.168.56.100

And/or can set your preferred Authentication method:

ssh -o PreferredAuthentications=password user@192.168.56.100

You can also do this in your SSH config file, /home/jared/.ssh/config.

Passwordless Login

Generate key

• help.ubuntu.com > Internet and Networking > SSH > Public and Private Keys
• Generating SSH Keys

Some examples:

ssh-keygen -t rsa -b 4096 -f mykeyfile -C "jared.flack@gmail.com"
ssh-keygen -t rsa -b 4096 -f github.com -C "jared@ethode.com"
ssh-keygen -t rsa -b 4096 -f dev.utees.com -C "jared@ethode.com"

ssh-keygen -t rsa -b 4096 -f centos -C "flack@one-hundred.local"

Flag explanation:

• -t key type
• -C comment; used with github to identify user's email
• -b encryption level; default is 2048, use 4096
• -f filename

If the key file is named something besides the default id_rsa (if you use the -f flag), then you have to point ssh to the key file:

ssh -i ~/.ssh/mykey user@example.com

You can also just use the ssh config file (~/.ssh/config):

Host example.com
	IdentityFile ~/.ssh/mykey

Set up config file

You can optioally set up a config file to make things a little easier (indentation is optional too):

Host myshortname
	HostName mywebsite.com
	User myusername
	IdentityFile ~/.ssh/mykey

Now you can just ssh myshortname.

Set up the server

Add the contents of the public key you created (so mykeyfile.pub, not mypublickey) to ~/.ssh/authorized_keys. If the file or folder do not exist, create them.

If you need to install Git, see Git.md.