2.6. Connecting Without a Password or Passphrase
One of the most
frequently asked questions about SSH is: "How can I connect to
a remote machine without having to type a password or
passphrase?" As you've seen, an SSH agent can make this
possible, but there are other methods as well, each with different
tradeoffs. Here we list the available methods with pointers to the
sections discussing each one.
To use SSH clients for
interactive
sessions without a password or passphrase, you
have several options:
WARNING:
Another way to achieve password-less logins is to use an unencrypted
private key with no passphrase. Although this technique can be
appropriate for automation purposes, never do this for interactive
use. Instead, use the SSH agent, which provides the same benefits
with much greater security. Don't use unencrypted keys for
interactive SSH!
On the other hand, noninteractive, unattended programs such as
cron jobs or batch scripts may also benefit from
not having a password or passphrase. In this case, the different
techniques raise some complex issues, and we will discuss their
relative merits and security issues later. [
Section 11.1, "Unattended SSH: Batch or cron Jobs"]
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| 2.5. The SSH Agent |  | 2.7. Miscellaneous Clients |
