I have two linode VPS accounts and I want to back up one onto the other (the reasons are mainly for fun and to practice server administration.)

the short version

Duplicity isn't even asking for my password, but immediately says "invalid SSH password" (but I can ssh into the other server). why?

the long version

When I run duplicity /home/me scp://[email protected]//root/backup I get

Invalid SSH password
Running 'sftp  [email protected]' failed (attempt #1)
Invalid SSH password
Running 'sftp  [email protected]' failed (attempt #2)
Invalid SSH password
Running 'sftp  [email protected]' failed (attempt #3)

And it says Invalid SSH password immediately with no opportunity for me to actually type the password.

When I type duplicity full -v9 --num-retries 4 /home/me scp://[email protected]//root/backup I get

Main action: full
Running 'sftp  [email protected]' (attempt #1)
State = sftp, Before = 'Connecting to 97.107.129.67...
[email protected]'s'
State = sftp, Before = ''
Invalid SSH password
Running 'sftp  [email protected]' failed (attempt #1)

I can ssh into [email protected] fine, and in fact have the ip in known_hosts before I tried any of this. serer 1 (from which I'm running the duplicity command) is Linode's default Ubuntu 8 setup with only a handful of programs installed via apt-get. server 2 (represented by x.x.x.x) is literally only Linode's default Ubuntu 8 setup

I previously tried using SystemImager -- would that have changed settings in a destructive way? (I have removed and rebooted since then)

Isn't Duplicity supposed to prompt for password? Am I using it wrong? are there common mistakes/dependencies I need to know about? Is there any way that x.x.x.x could be setup that could make this not work (I used Linode's default Ubuntu 8 setup and barely )?