On Sunday 04 January 2009 11:32:24 Mike Cloaked wrote:
Anne Wilson-4 wrote:
Is a ssh key specific to a computer, or to a user? That is, does my key pertain to any box on the lan, as long as I'm the user? Or is it machine
ssh keys are specific to the user - they are in the users .ssh directory in their home user directory. Root also has its own .ssh
On the server side you can choose who to allow to connect and also whether to allow password connections and many other options in /etc/ssh/sshd_config and you can find more in "man sshd_config"
On my server I set that up to allow only connection with keys. I presume that any box that might need to be monitored by ssh will need the same treatment.
You need to look up how to generate ssh keys and store them. It is possible to replicate the .ssh directory for your own user area and put it on the user area of the same name on a different computer to save the need to generate new keys.
I feel unsafe about storing keys on a laptop that is going to travel, so I'll need to read up on storing them on a usb stick. At least losing the stick will not make the connection unsafe :-) - I'm unlikely to lose the laptop and stick at the same time.
However you also need to be aware that the system will know if the remote machine you are connecting to is upgraded - and then when you try to ssh in you will get a warning saying there is a possible man-in-the middle attack. In this instance if the remote machine is known to have been reinstalled for example then in the user area from which you are trying to connect need to have the entry in .ssh/known_hosts removed by editing (or remove the known_hosts file) and accept prompts the first time you then subsequently ssh into another machine.
OK - this is probably not an issue on the server, which runs CentOS, but would be much more so on workstations and laptops.
There are tutorials on the net and a google search will find them fairly easily.
Yes, I set it up from such a tutorial, but sometimes I need to check that I have understood/remembered something correctly. Especially when it concerns something relevant to security.
Anne