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I had my keys set up so I can ssh between machines without having to enter a password and everything was working for a while but then, all of a sudden, I'm being prompted for a password on some machines. I verified the keys - everything appears to be OK. I ran ssh -v and here is the output. From what I can tell, the key is being verified successfully, so why am I asked to enter a password???

ssh XXX.XXX.XXX.XXX -v
OpenSSH_4.3p2, OpenSSL 0.9.8e-fips-rhel5 01 Jul 2008
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Applying options for *
debug1: Connecting to XXX.XXX.XXX.XXX [XXX.XXX.XXX.XXX] port 22.
debug1: Connection established.
debug1: identity file /nethome/username/.ssh/identity type -1
debug1: identity file /nethome/username/.ssh/id_rsa type 1
debug1: identity file /nethome/username/.ssh/id_dsa type 2
debug1: loaded 3 keys
debug1: Remote protocol version 2.0, remote software version OpenSSH_5.3
debug1: match: OpenSSH_5.3 pat OpenSSH*
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_4.3
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: server->client aes128-ctr hmac-md5 none
debug1: kex: client->server aes128-ctr 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 'XXX.XXX.XXX.XXX' is known and matches the RSA host key.
debug1: Found key in /nethome/username/.ssh/known_hosts:43
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,gssapi-keyex,gssapi-with-mic,password
debug1: Next authentication method: gssapi-with-mic
debug1: Unspecified GSS failure.  Minor code may provide more information
No credentials cache found

debug1: Unspecified GSS failure.  Minor code may provide more information
No credentials cache found

debug1: Unspecified GSS failure.  Minor code may provide more information
No credentials cache found

debug1: Next authentication method: publickey
debug1: Trying private key: /nethome/username/.ssh/identity
debug1: Offering public key: /nethome/username/.ssh/id_rsa
debug1: Authentications that can continue: publickey,gssapi-keyex,gssapi-with-mic,password
debug1: Offering public key: /nethome/username/.ssh/id_dsa
debug1: Authentications that can continue: publickey,gssapi-keyex,gssapi-with-mic,password
debug1: Next authentication method: password

By the way, I don't see a message that server accepted the authentication:

debug1: Server accepts key: pkalg ssh-rsa blen 277

~/.ssh/ has mode 700, I tried running ssh-copy-id and that seems to have worked. Just to be sure, I ran md5sum on id_rsa.pub on both machines and they are the same. Also, the checksum on authorized_keys on the target machine, matches to the checksum of the public key (since it's the only key in authorized keys).

  • The term firewall comes to mind here....or at least iptables on one or the other hosts. – mdpc Oct 7 '14 at 22:00
  • Are you using SE Linux? Also I assume the permissions are actually: chmod 700 ~/.ssh && chmod 600 ~/.ssh/* (check it's like this on the machines that aren't working) – rainkinz Oct 7 '14 at 22:58
  • I'm using different version of RHEL (5.8 and 6.4 mostly). Pretty sure it's just off the shelf RHEL distro. The .pub files, as well as known_hosts are 644, authorized_keys is 640, the private keys (on the machines that have them) are all 600. – ventsyv Oct 8 '14 at 18:57
  • The key that is successfully verified is the server's host key - your own private key is not being verified successfully. Do you have access to the sshd logs of the remote server? Also, what are the permissions of your own home directory on the remote server? – Jenny D Oct 13 '14 at 7:34
5

Turns out that not only .ssh but $HOME permissions matter! $HOME has to have permissions set no higher than 751.

protected by Community Dec 27 '18 at 13:11

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