Hi,

I would like to scp from my linux box to a pc w/out a password. The linux is "stargate" and pc is "joannah"

I have set public/private keys such that my linux has /root/.ssh/id_dsa.pub and my pc has /home/.ssh/authorized_keys and /home/.ssh/authorized_keys2.


Sometimes, when i do:

scp file johndoe@my_ip.edu:

the file transfers ok, with no warning and no need to enter password. but sometimes i get the error:
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the rsa host key for my_ip.edu has changed and the key for the according IP address 123.4.5.6 is unknown. this could iehter mean that dns spoofing is happening or the ip address for the host and its host key have changed at the same time

it is possible that someone is doing something nasty! someone could be eavesdropping on you right now (man-in-the-middle attack)! is is also possible that the rsa host key has just been changed. please contact your system administrator. add correct host key in /root/.ssh/known_hosts to get rid of this message. rsa host key for seas.ucla.edu has changed and you have requested strict checking.
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i'm not sure why sometimes the scp works and sometimes it fails and i get warning above.

any comments would be appreciated.

Thanks!

It tells you it could be an attack so you can't rule that out.

However I'm guessing you're running DHCP on your Linux box so its IP is changing. As noted in the message you see that's one of the things that could cause the problem. DHCP sets your IP from a range of possible IPs allowed. If this is on a home network and you're using a router just make sure to always plug into the same port to get the same IP. If its in an office setting you may need to ask whoever runs the DHCP server to give you a static address or at least increase the reservation time so it doesn't lose it quickly.