Thanks for the reply Stefan...

# yum list installed | grep openssh

openssh.x86_64                           5.3p1-53.moonshot1.el6.5       installed
openssh-askpass.x86_64                   5.3p1-53.moonshot1.el6.5       installed
openssh-clients.x86_64                   5.3p1-53.moonshot1.el6.5       installed
openssh-ldap.x86_64                      5.3p1-53.moonshot1.el6.5       installed
openssh-server.x86_64                    5.3p1-53.moonshot1.el6.5       installed

So I think that should be using the right one. Just to confirm, selinux is set to disabled, and the GSSAPI directives are enabled in ssh_config and sshd_config (although GSSAPIStrictAcceptorCheck doesn't appear highlighted in vim colour syntax). The SSH test fails with this set to yes or no.

I've included a debug of the ssh transaction below this mail (this is with GSSAPIStrictAcceptorCheck set to yes).

Thanks,
John

(root)# /usr/sbin/sshd -d
debug1: sshd version OpenSSH_5.3p1
debug1: read PEM private key done: type RSA
debug1: private host key: #0 type 1 RSA
debug1: read PEM private key done: type DSA
debug1: private host key: #1 type 2 DSA
debug1: rexec_argv[0]='/usr/sbin/sshd'
debug1: rexec_argv[1]='-d'
Set /proc/self/oom_score_adj from 0 to -1000
debug1: Bind to port 22 on 0.0.0.0.
Server listening on 0.0.0.0 port 22.
debug1: Bind to port 22 on ::.
Server listening on :: port 22.

** command invoked below happens here **

debug1: Server will not fork when running in debugging mode.
debug1: rexec start in 5 out 5 newsock 5 pipe -1 sock 8
debug1: inetd sockets after dupping: 3, 3
Connection from 130.209.8.70 port 45700
debug1: Client protocol version 2.0; client 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: list_hostkey_types: ssh-rsa,ssh-dss
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: client->server aes128-ctr hmac-md5 none
debug1: kex: server->client aes128-ctr hmac-md5 none
debug1: SSH2_MSG_KEX_DH_GEX_REQUEST received
debug1: SSH2_MSG_KEX_DH_GEX_GROUP sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_INIT
debug1: SSH2_MSG_KEX_DH_GEX_REPLY sent
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
Connection closed by 130.209.8.70
debug1: do_cleanup


(me)# ssh -v [log in to unmask]
OpenSSH_5.3p1, OpenSSL 1.0.0-fips 29 Mar 2010
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Applying options for *
debug1: Connecting to moonshot-vm1.cent.gla.ac.uk [130.209.8.70] port 22.
debug1: Connection established.
debug1: identity file /home/me/.ssh/identity type -1
debug1: identity file /home/me/.ssh/id_rsa type -1
debug1: identity file /home/me/.ssh/id_dsa 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: 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: Unspecified GSS failure.  Minor code may provide more information


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

debug1: Offering GSSAPI proposal: gss-gex-sha1-JHo1wNMhky/7DkDu4d6xCA==,gss-group1-sha1-JHo1wNMhky/7DkDu4d6xCA==,gss-group14-sha1-JHo1wNMhky/7DkDu4d6xCA==,gss-gex-sha1-dEYdZI86nhHqawDlBMslQw==,gss-group1-sha1-dEYdZI86nhHqawDlBMslQw==,gss-group14-sha1-dEYdZI86nhHqawDlBMslQw==
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 'moonshot-vm1.cent.gla.ac.uk' is known and matches the RSA host key.
debug1: Found key in /home/me/.ssh/known_hosts:1
ssh_rsa_verify: EVP_get_digestbynid 64 failed
key_verify failed for server_host_key