Does DreamHost offer ssh for all accounts or just the dedicated accounts?
As Matttail says, SSH log-ins are available on all DreamHost plans.
However, you will need to enable it for each user you wish to have SSH access. This is done in the Admin Panel at Users -> Manage Users. Click the Edit link on the particular user, then tick the Enable ssh/telnet? checkbox. It can take a little while before the change takes place.
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