The Univention Management Console (UMC) is a modularly designed, web-based application for the administration of individual Univention Corporate Server systems.
Should a problem arise when logging on to UMC, the following error message may appear, for example:
Authentication error: The UMC server has not answered the authentication request
This means that the UMC server has not reacted to the authentication request of the web frontend. As this can have many causes, a number of points – described in detail below – must be checked.
Is the UMC server running?
This could most likely be indicated by:
503 Internal server error: The service is temporarily not available.
check if the server and web-server are running and restart them if not
ps waux | grep univention-management-console-server
Is the LDAP server running? (only on DC master, DC backup, DC slave)
univention-ldapsearch -s base -h $(ucr get hostname).$(ucr get domainname)
Checking SSL certificates
Is the system time correct?
The configuration of the system time is described in the UCS manual in the chapter “Time Synchronisation”
Have the SSL certificates expired?
univention-certificate dump -name $(ucr get hostname).$(ucr get domainname) | egrep -i -A2 'validity';
If the certificates have expired/are invalid: The renewal of SSL certificates is described in the SDB article Renewing the SSL certificates .
Checking name resolution
Are the Univention DNS services (univention-bind und univention-bind-proxy) running?
ps waux | grep bind
Are correct name servers set?
ucr search nameserver
Can server name to IP and IP to server name be correctly resolved?
host $(ucr get hostname).$(ucr get domainname)
host $(ucr get interfaces/eth0/address)
Is the Kerberos service record correctly resolvable?
host -t SRV _kerberos._tcp.$(ucr get domainname)
Checking the Kerberos settings
Obtain Kerberos ticket with kinit
Checking log files for relevant messages
More messages may appear at an increased debug level. Proceed as follows to increase the debug level:
Stop the UMC server:
ucr set umc/server/debug/level=4
Finally, perform a new log-in to UMC and check the /var/log/univention/management-console-server.log log file for relevant messages. After the test, the debug level should be returned to the original level.
Checking the translation files
It is possible that one of the translation files gets corrupt - you can determine this in the logs:
grep "error: unpack requires a string argument of length 4" /var/log/univention/management-console-server.log | echo $?
If you receive “0” as a result (or find this string as a traceback by hand), the string was found in the logfile and the following steps should help:
mv /usr/share/ univention-management-console/i18n/de/apps.mo /root/apps.mo