Author Archives: Hermann Maurer
Notes on usage of Check_MK Multisite with LDAPS
I had to configure OMD/Check_MK version 1.2.4p3 to use LDAPS to connect to Windows domain controller. The operating system on the host running OMD/Check_MK is CentOS 6.5 x64.
Postfix in Internet, Relay in LAN
Assume the following scenario:
Your Postfix MTA is located in the Internet (having a public IP address) and you have configured an external DNS server there to be used for DNS requests. But you are going to send mails using an internal mail server as mail relay. In this case the private IP address of the internal mail relay cannot be re-solved by the external DNS server. In this situation Postfix cannot use the mail relay and shows an error message like this below in the log file:
Aug 26 12:49:12 myclient postfix/error[28425]: B35AF34B: to=<me@company.local>, relay=none, delay=0.14, delays=0.09/0/0/0.04, dsn=4.3.5, status=deferred (delivery temporarily suspended: Host or domain name not found. Name service error for name=mailrelay.company.local type=AAAA: Host not found)
To re-solve the issue you have to add the following statement to main.cf
disable_dns_lookups = yes
and re-load postfix:
service postfix reload
Use the appropriate command to enforce delivery of queued mails.
Some useful postfix commands
To re-try delivering of queued mails:
postqueue -f
To remove all deferred mails:
postsuper -d ALL deferred
To remove all mails
postsuper -d ALL
Insufficient system resources (in reply to MAIL FROM command)
If you see an error like this while trying to send an email via your Exchange server
E32F1291C 5322 Tue Aug 26 09:15:08 MAILER-DAEMON (host yourexchangeserver.com[10.10.10.10] said: 452 4.3.1 Insufficient system resources (in reply to MAIL FROM command))
then the system partition of the Exchange server has become low on free space. I have been watching this, if the free space on the drive C: of my server becomes less then 6% of the whole partition size. These are still more than 3 GByte!
You don’t need to do anything on the Exchange server but to free some additional space.
OMD: If PNP4Nagios XML file has changed
Assume the following situation:
You changed something on a service and the performance data format has changed as well. PNP4Nagios graphs that belong to the changed service will not be changed automatically. You have to remove the old XML file that belongs to the changed service and then re-start your OMD site completely like this:
OMD[mysite]:~$ rm var/pnp4nagios/perfdata/webserver35/Apache_127.0.0.1_80_Status.xml
OMD[mysite]:~$ omd restart
In a few minutes the XML file should be re-generated and graphs belonging to new performance data counters should appear. If NOT, I’m afraid that you have to remove all RRD-files that belong to the service (you can recognize it on the file name) and to hope that they will be re-created properly. In this case all the server statistic will be lost (you have been warned!).
Neues Fotoalbum von unserem Sommerurlaub in Frankreich
Endlich ist es soweit und habe jede Menge Fotos auf PicaseWeb hochgeladen. Hier ist das neue Fotoalbum zu besichtigen: