Dear Linux Gurus,

In a bit of a pickle at the moment.

We experienced multiple power cuts on Monday just gone resulting in power less (UPS's ran out of juice!) to 1 client machine and 5 CFD cluster servers (all bare metal). Since then, one primary user account has loss the ability to remotely connect to any of the 5 servers using passwordless SSH.

Steps I've taken:

Regenerated new private and public keys using ssh-keygen (following official RH instructions: https://access.redhat.com/solutions/9194)
Copied over new public key to servers using ssh-copy-id and manually.

Client is Centos 6.9 and Servers are RHEL 6.9.

The /home directory is an NFS mount point on the client and servers are from a different server (so all the same) - would this effect proceedings? Been set up like this before with no issues.

I'm an intermediate user of Linux but this has completely stumped me.

Any help or suggestions would be greatly appreciated.

TIA and cheers!

Edit: Here is a -v verbose output from the client trying to connect to one server:

ssh -v sdlpmcfd01
OpenSSH_5.3p1, OpenSSL 1.0.1e-fips 11 Feb 2013
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Applying options for *
debug1: Connecting to sdlpmcfd01 [10.0.210.36] port 22.
debug1: Connection established.
debug1: identity file /home/mmccarthy/.ssh/identity type -1
debug1: identity file /home/mmccarthy/.ssh/identity-cert type -1
debug1: identity file /home/mmccarthy/.ssh/id_rsa type 1
debug1: identity file /home/mmccarthy/.ssh/id_rsa-cert type -1
debug1: identity file /home/mmccarthy/.ssh/id_dsa type -1
debug1: identity file /home/mmccarthy/.ssh/id_dsa-cert type -1
debug1: identity file /home/mmccarthy/.ssh/id_ecdsa type -1
debug1: identity file /home/mmccarthy/.ssh/id_ecdsa-cert type -1
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_5.3
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: server->client aes128-ctr hmac-sha1 none
debug1: kex: client->server aes128-ctr hmac-sha1 none
debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(1024<2048<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 'sdlpmcfd01' is known and matches the RSA host key.
debug1: Found key in /home/mmccarthy/.ssh/known_hosts:1
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-keyex
debug1: No valid Key exchange context
debug1: Next authentication method: gssapi-with-mic
debug1: Unspecified GSS failure. Minor code may provide more information
Credentials cache file '/tmp/krb5cc_502' not found

debug1: Unspecified GSS failure. Minor code may provide more information
Credentials cache file '/tmp/krb5cc_502' not found

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

Okay! Right, so.. I've gone into the sshd_config and changed StrictMode to no and it now works. This leads me to believe it's purely permissions based.

I've made sure to make .ssh folder 700 and authorized_keys as 600.

For now, I need to leave StrictMode to no for a user to carry on working but this isn't the base case.

Hi,

I got a similar error once, it was related to SELinux context distortion. I'd suggest you to switch it to "permissive" mode and try connecting again. If it helps then you'll need to restore the context using
Thanks