Feb 24 2009 login

ssh tips

Password-less authentication:

generate public and private key (e.g. with ssh-keygen -q -f ~/.ssh/id_rsa -t rsa) (or -t dsa)
on the machine from which you connect: put private key in ~/.ssh/id_rsa (for rss key) or ~/.ssh/id_dsa (for dsa key), with 0600 permissions
on the machine you connect to: append public key to ~/.ssh/authorized_keys (also with 0600 permission)

Using a different username with svn+ssh:

By default ssh uses $USER when connecting to a server. This makes things difficult if you use svn with ssh authentication and your username for svn server is different than $USER. To get around this define per host SSH settings. To do this, edit ~/.ssh/config and add the lines:

Host svn.yourserver.com
User jdoe

That instructs ssh to use the username jdoe instead of your unix username when connecting to svn.youserver.com. If you use password-protected ssh keys, you will be prompted for a private key password, like this:

Enter passphrase for key '/home/jdoe/.ssh/id_dsa':

To get around this you can either setup ssh-agent to cache this password or you can turn off the password on your private key. To do the latter: ssh-keygen -t dsa -p and when it prompts for a new passphrase, just hit enter.

Using ssh agent:

Ssh agent remembers password for your private key, so you only have to type it once in a session, not every time it’s used.

Start ssh agent: ssh-agent
Add keys: ssh-add
List currently loaded keys: ssh-add -l

Cygwin and ssh agent:

Links:

Add this to ~/.bashrc:

## Enable ssh agent
export SSH_AUTH_SOCK=/tmp/.ssh-socket

ssh-add -l >/dev/null 2>&1

if [ $? = 2 ]; then
  # Exit status 2 means couldn't connect to ssh-agent; start one now
  rm -rf /tmp/.ssh-*
  ssh-agent -a $SSH_AUTH_SOCK >/tmp/.ssh-script
  . /tmp/.ssh-script
  echo $SSH_AGENT_PID >/tmp/.ssh-agent-pid
fi

function kill-agent {
  pid=`cat /tmp/.ssh-agent-pid`
  kill $pid
}

function addkeys {
  ssh-add ~/.ssh/id_dsa*
}

Set an alias for a hostname

In ~/.ssh/config:

Host dev30
HostName dev30.kowalczyk.info
User root
IdentityFile ~/.ssh/id_dsa_opendns

← newer • 123 of 661 • older →

Krzysztof Kowalczyk Blog • Notes • My Software • My Documents

ssh tips