scp error: "Permission denied (publickey). lost connection"

Solution 1:

Did you expect to be prompted for a password? If so, then something in your ssh or the remote server's sshd configuration's changed to disallow password authentication.

Otherwise, your debug output seems to be saying that your private keys don't match any of the public keys in the remote account's .ssh directory. Have you compared the ~/.ssh/id_?sa.pub files on savannah to the output from ssh-keygen -y on your local box?

Another possibility is that the permissions on your .ssh files are too permissive. I believe I've seen that happen without any output, debug or otherwise, to hint at it.

Solution 2:

This is a authentication error, there is not a matching key to pair to.

When having problems with ssh or using ssh over scp as your doing the -v switch is very informative to diagnose the problem, the more v's you put in there the more verbose the output:

scp -vvv -P 30000 /somedir/somedir/file user@domain:/somedir/somedir/

Here is a sample output of it:

OpenSSH_6.7p1 Debian-5+deb8u7, OpenSSL 1.0.1t  3 May 2016
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: Applying options for *
debug2: ssh_connect: needpriv 0
debug1: Connecting to 192.168.1.171 [192.168.1.171] port 30000.
debug1: Connection established.
debug1: permanently_set_uid: 0/0
debug1: key_load_public: No such file or directory
debug1: identity file /root/.ssh/identity type -1
debug1: key_load_public: No such file or directory
debug1: identity file /root/.ssh/identity-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /root/.ssh/id_rsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /root/.ssh/id_rsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /root/.ssh/id_dsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /root/.ssh/id_dsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /root/.ssh/id_ecdsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /root/.ssh/id_ecdsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /root/.ssh/id_ed25519 type -1
debug1: key_load_public: No such file or directory
debug1: identity file /root/.ssh/id_ed25519-cert type -1
debug1: Remote protocol version 2.0, remote software version OpenSSH_7.4p1 Debian-10+deb9u4
debug1: match: OpenSSH_7.4p1 Debian-10+deb9u4 pat OpenSSH* compat 0x04000000
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_6.7p1 Debian-5+deb8u7
debug2: fd 3 setting O_NONBLOCK
debug3: put_host_port: [192.168.1.171]:30000
debug3: load_hostkeys: loading entries for host "[192.168.1.171]:30000" from file "/root/.ssh/known_hosts"
debug3: load_hostkeys: found key type ECDSA in file /root/.ssh/known_hosts:7
debug3: load_hostkeys: loaded 1 keys
debug3: order_hostkeyalgs: prefer hostkeyalgs: [email protected],[email protected],[email protected],ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received

You could check if the permissions on the ssh files are rightly set, you can see the right permissions below in my ls command

There maybe is someone who deleted your key from the server.

Or as in the comments someone said, maybe you don't have a matching private key?

To create a ssh key if anyone needs that at this stage, this is how you do that:

ssh-keygen -o -b 4096 -t rsa -C [email protected]

that creates a private key and a public key in ~/.ssh/ directory, be careful never to share your private key, that's the id_rsa....notice that ~/.ssh/ has a dot in front of it because it's a hidden directory like here:

$ls -sail .ssh/
total 20
  658 4 drwx------  2 user user 4096 Nov 10 06:05 .
   12 4 drwxr-xr-x 47 user user 4096 Nov 10 06:11 ..
34211 4 -rw-r--r--  1 user user 1487 Nov  1 02:37 authorized_keys
34375 4 -rw-------  1 user user 3434 Nov 10 06:05 id_rsa
34376 4 -rw-r--r--  1 user user  749 Nov 10 06:05 id_rsa.pub
  664 0 -rw-r--r--  1 user user   0 Nov 10 06:04 known_hosts

then to copy the key over to the server:

cat ~/.ssh/id_rsa.pub | ssh -p 30000 something@SERVER 'cat >> .ssh/authorized_keys'

You need to get your public ssh key to the server and if you don't have access to it in physical and can edit sshd_config to allow passwords

 # Change to no to disable tunnelled clear text passwords
 PasswordAuthentication no

while you copy it, you could email it to the system administrator and he can put it on the server.