ssh publickey authentication

spx2 · 12-28-2007, 11:46 AM

I have followed all the stepts described here
http://sial.org/howto/openssh/publickey-auth/
up until "Ket Access Limits"
and when I try to enter the server from the client I get
this

Code:

stef@stefan:~$ ssh -o PreferredAuthentications=publickey spx2@firepower
Permission denied (publickey,password).
stef@stefan:~$

fuzzyworm · 12-28-2007, 01:11 PM

On the server-side, log in as the user and do:

Code:

cd ~/.ssh
ls -l

Look for authorized_keys, check the spelling (i.e. US English spelling of authorized), and check that the permissions are at least 'read' for the user. Also, make sure that the contents of your public key is sitting within this file somewhere:

Code:

cat authorized_keys | grep --file=id_rsa.pub

On the client side, check the file name for your own private key. You may need to specify the name on the ssh command line, i.e.:

Code:

$ ssh -i myid_rsa.prv -o PreferredAuthentications=publickey spx2@firepower

Hope this is of some help, let me know if this doesn't work.

spx2 · 12-29-2007, 06:06 AM

I have tried what you wrote here and I still get the same error

digen · 12-29-2007, 09:04 AM

Try verbose output in the ssh command and see what is going on,

Quote:

ssh -v -o PreferredAuthentications=publickey spx2@firepower

bakfupai · 12-29-2007, 12:40 PM

check the permissions of the key on the client. might be that one that has permissions that makes it unreadable. anyway, I'm pretty sure that if you use SSH2 (which you should!) the file on the server is named ~/.ssh/authorized_keys2

spx2 · 12-30-2007, 07:31 AM

@digen
the output of verbose ssh

Code:

OpenSSH_4.6p1 Debian-5, OpenSSL 0.9.8e 23 Feb 2007
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Applying options for *
debug1: Connecting to firepower [192.168.1.3] port 22221.
debug1: Connection established.
debug1: identity file /home/stef/.ssh/identity type -1
debug1: identity file /home/stef/.ssh/id_rsa type 1
debug1: identity file /home/stef/.ssh/id_dsa type -1
debug1: Remote protocol version 2.0, remote software version OpenSSH_4.3p2 Debian-9
debug1: match: OpenSSH_4.3p2 Debian-9 pat OpenSSH*
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_4.6p1 Debian-5
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: server->client aes128-cbc hmac-md5 none
debug1: kex: client->server aes128-cbc hmac-md5 none
debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(1024<1024<8192) sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP
debug1: SSH2_MSG_KEX_DH_GEX_INIT sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY
debug1: Host '[firepower]:22221' is known and matches the RSA host key.
debug1: Found key in /home/stef/.ssh/known_hosts:12
debug1: ssh_rsa_verify: signature correct
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug1: SSH2_MSG_NEWKEYS received
debug1: SSH2_MSG_SERVICE_REQUEST sent
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug1: Authentications that can continue: publickey,password
debug1: Next authentication method: publickey
debug1: Trying private key: /home/stef/.ssh/identity
debug1: Offering public key: /home/stef/.ssh/id_rsa
debug1: Authentications that can continue: publickey,password
debug1: Trying private key: /home/stef/.ssh/id_dsa
debug1: No more authentication methods to try.
Permission denied (publickey,password).

fuzzyworm · 12-30-2007, 11:31 AM

Quote:

Originally Posted by bakfupai

... I'm pretty sure that if you use SSH2 (which you should!) the file on the server is named ~/.ssh/authorized_keys2

Not any more:

http://sial.org/howto/openssh/#s6

fuzzyworm · 12-30-2007, 11:36 AM

Are you using a passworded key? Are you sure that you've got the password right? Try using a key with no password, or a simple password first, just to test the system, and then replace it once you know everything works.

Also, try tightening up the permissions of the .ssh folder:

Code:

chmod 600 -R ~/.ssh

on both machines

spx2 · 12-31-2007, 09:34 PM

ok,I've put appropriate permissions,
I've tried again,and I've got some better
debug output from verbose switch output.
here are those messages:

Code:

debug1: match: OpenSSH_4.3p2 Debian-9 pat OpenSSH*
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_4.3p2 Debian-9
debug1: An invalid name was supplied
Configuration file does not specify default realm

debug1: An invalid name was supplied
A parameter was malformed
Validation error

debug1: An invalid name was supplied
Configuration file does not specify default realm

debug1: An invalid name was supplied
A parameter was malformed
Validation error

debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: server->client aes128-cbc hmac-md5 none
debug1: kex: client->server aes128-cbc hmac-md5 none
debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(1024<1024<8192) sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP
debug1: SSH2_MSG_KEX_DH_GEX_INIT sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY
debug1: Host 'firepower' is known and matches the RSA host key.
debug1: Found key in /home/spx2/.ssh/known_hosts:4

spx2 · 01-07-2008, 08:19 PM

I've deleted all .ssh on both machines and started all over.
suppose the machines are called A and B.
I've done this
A/.ssh/id_rsa.pub -> B/.ssh/authorized_keys
B/.ssh/id_rsa.pub -> A/.ssh/authorized_keys
Now I can do ssh from A->B but not B->A.

Was the first one enough to be able to ssh both ways with public keys
or was thesecond one needed ?

fuzzyworm · 01-10-2008, 05:55 PM

In order to ssh from A to B, B needs to have the contents of A's 'id_rsa.pub' file in its authorized_keys file.

Similarly, in order to ssh from B to A, A needs the contents of B's 'id_rsa.pub' file in its authorized_keys file.

So, if you want to go both ways, then yes, you do need to do both.

Is it working now then?

spx2 · 01-11-2008, 05:27 AM

I can do A->B but not B->A.
I have checked error logs and -v -o output of ssh but I can't identify the problem