Robert Dailey wrote:

> I'm very new to Ubuntu Server and I'm just wondering what the key named
> "ssh_host_dsa_key" is for?

You have host key pairs for your users and for your hosts.  This is the
_private_ dsa key for your machine.  ssh_host_dsa_key.pub is the one that
other machines use to verify that they're still connecting to the same
machine with repeated uses.

> This is located in /etc/ssh. Also another
> confusing concept is ssh-keygen. What's the point of creating
> public/private keys?

You have host key pairs for your users and for your hosts... :-)

> Is this so I never need to specify an explicit
> password when logging into my ubuntu server via PuTTY on windows?

When you're logging into _any_ ssh server with any ssh client, not just
PuTTY.  And this is not just a convenience for you - it's actually more
secure to not send passwords over the network.  I run ssh_keygen once, then
login (with a password) to a server and append the public key to
~/.ssh/authorized_keys, and I never have to use a password again (this,
though, causes havoc with the machine I only occasionally administer, as I
then need to remember the "login password", that I never use to login, for
sudo).

> I'm
> trying to understand how SSH works in Ubuntu so I can debug an issue I'm
> having with svn over ssh.

Try telling us what the issue is...