On a server where the user authentication happens on a Windows Active Directory, I saw the following errors when a user tried to log in with SSH:
sshd: pam_winbind(sshd:account): valid_user: wbcGetpwnam gave WBC_ERR_DOMAIN_NOT_FOUND
A test of the current winbind settings with the command wbinfo showed that there is indeed a problem:
checking the trust secret for domain EXAMPLE via RPC calls failed
error code was NT_STATUS_DOMAIN_CONTROLLER_NOT_FOUND (0xc0000233)
Failed to call wbcCheckTrustCredentials: WBC_ERR_AUTH_ERROR
Could not check secret
I tried to join the machine to the domain again, but it failed:
net ads join -U EXAMPLE\aduser
Failed to join domain: failed to lookup DC info for domain 'EXAMPLE.COM' over rpc: NT_STATUS_CONNECTION_RESET
However the correct information was shown when net ads info was launched:
net ads info
LDAP server: 192.168.40.10
LDAP server name: DC001.example.com
Bind Path: dc=EXAMPLE,dc=COM
LDAP port: 389
KDC server: 192.168.40.10
Server time offset: 0
After a lot of googling and after having launched winbindd manually with a high debug level, I finally came across a blog post, which described similar problems and that they were solved by deleting the computer in the primary domain controller (PDC).
First I stopped the winbind daemon and verified that all processes were gone:
ps aux | grep winbind
Then I left the domain:
net ads leave -U aduser
Deleted account for 'LINUXSERVER' in realm 'EXAMPLE.COM'
I verified on the domain controller, that the computer really disappeared. Then I created a backup of /var/lib/samba and deleted all *tdb files:
cp -Rp /var/lib/samba /root/samba-tdb-bkp-$(date +%Y%m%d)
Now I joined the domain again:
net ads join -U aduser
Using short domain name -- EXAMPLE
Joined 'LINUXSERVER' to dns domain 'example.com'
This took a while (around 1-2 mins) and once done new tbd files have appeared in /var/lib/samba/.
The computer "LINUXSERVER" could now be found on the PDC again, in the default "Computers" folder.
Time to start winbind again:
... and verify if communication with the AD now works again:
checking the trust secret for domain EXAMPLE via RPC calls succeeded
From now on the SSH login was working again.
Read more on a follow-up article (getent passwd does not show Active Directory users, but wbinfo -u works fine) which contains a check list what to verify when AD users don't show up on Linux.
ck from Switzerland wrote on Nov 21st, 2016:
Thanks none, corrected in the post.
none from asdf wrote on Nov 21st, 2016:
There is a typo:
-> rm /var/lib/samba/*.tdb
AWS Android Ansible Apache Apple Atlassian BSD Backup Bash Bluecoat CMS Chef Cloud Coding Consul Containers CouchDB DB DNS Database Databases Docker ELK Elasticsearch Filebeat FreeBSD Galera Git GlusterFS Grafana Graphics HAProxy HTML Hacks Hardware Icinga Icingaweb Icingaweb2 Influx Internet Java KVM Kibana Kodi Kubernetes LXC Linux Logstash Mac Macintosh Mail MariaDB Minio MongoDB Monitoring Multimedia MySQL NFS Nagios Network Nginx OSSEC OTRS Office PGSQL PHP Perl Personal PostgreSQL Postgres PowerDNS Proxmox Proxy Python Rancher Rant Redis Roundcube SSL Samba Seafile Security Shell SmartOS Solaris Surveillance Systemd TLS Tomcat Ubuntu Unix VMWare VMware Varnish Virtualization Windows Wireless Wordpress Wyse ZFS Zoneminder