My posts about issues concerning Linux OS and network administration

Monitoring postfix with Zabbix (LTS version 3.0)

Posted on:
May 6, 2016
Author:
Tomas Brandysky

As we’ve built new monitoring system based on Zabbix LTS version 3.0 I also was looking for solution how to monitor postfix servers. I’ve found few articles regarding this issue but they were either outdated or not very effective. I decided to take the best from what I’ve found but build an own strategy. The […]

Posted in Monitoring | 4 Comments

Configuring and running virtual SAN with StarWind software

Posted on:
February 25, 2015
Author:
Tomas Brandysky

Since we decided to run our production server on 2-node vSphere virtual cluster connected to single SAS disk array where all data is stored we’d like to guarantee this array to be fault tolerant not only when controller (there are actually two redundant controllers) or single disk (secured with raid array) is concerned but as […]

Posted in High availability, Virtualization | 4 Comments

How to backup vSphere’s virtual machine configurations automatically

Posted on:
July 8, 2014
Author:
Tomas Brandysky

We decided to setup some simple solution to backup configurations of all virtual machines in our virtualization cluster as this definitely could come in handy in case of data loss when these virtual machines would need to be restored along with their original configurations. I was searching for a simple solution on Internet for a […]

Posted in Backups, Server administration | 2 Comments

Advanced Bacula management – getting rid of unused Bacula volumes

Posted on:
December 18, 2013
Author:
Tomas Brandysky

I’ve been using Bacula software for couple of years in different companies and in different configurations. Bacula is a great and complex backup software which can compete with big commercial backup solutions in some ways but it also have some cons you have to deal with when implementing it in production environment. One of the […]

Posted in Backups | No Comments

Synchronizing users from LDAP to Active Directory

Posted on:
September 5, 2013
Author:
Tomas Brandysky

Since we decided to implement Active Directory in our company to take control of user’s desktops there rose up the idea of synchronizing users between LDAP and AD. The optimal solution would be two-way synchronization between our LDAP server and Active Directory server including user login, email, full name and his password. After we had […]

Posted in Server administration | No Comments

Annoying Cisco ASA bug in IOS 8.4.5 and 8.4.6 – ERROR: NAT Policy is not downloaded

Posted on:
August 29, 2013
Author:
Tomas Brandysky

It’s been already few month when we upgraded ASA box to 8.4.6 IOS version. I needed to add new NAT rules and ended up with error “ERROR: NAT Policy is not downloaded”. After contacting local Cisco support I was told this is a known issue and the workaround is to remove all NAT configuration and […]

Posted in ASA 5000 series, Cisco devices configuration | No Comments

Custom maintenance page defined as an DNS record

Posted on:
April 25, 2013
Author:
Tomas Brandysky

If you are running a web page on server which needs to be taken down due to maintenace reasons you probably need to cope with unrachability of your page during the downtime. This is generally done by serving a simple maintenance page explaining the reasons of downtime and estimated time when the page will be […]

Posted in High availability, Server administration | No Comments

LDAP replication with OpenLDAP 2.3 and Centos/RHEL 5

Posted on:
April 25, 2013
Author:
Tomas Brandysky

OpenLDAP version 2.3 comes with new LDAP Content Synchronization protocol which is described in RFC 4533 and is generally known as syncrepl. The older slurpd approach is obsolete and isn’t supported from OpenLDAP 2.4 Although syncrepl supports both master-slave and multi-master replications, there is only support for master-slave in OpenLDAP version 2.3 which also is […]

Posted in Server administration | No Comments

How to debug crashing application on RHEL/Centos systems

Posted on:
April 23, 2013
Author:
Tomas Brandysky

We are running bunch of our applications on production Centos 5 servers and it happens sometimes that one of the processes crashes unexpectedly but not so often so that we could reproduce the behaviour and localize the problem. At this point having a possibility to turn on the debug mode in Linux definitely comes in […]

Posted in Server administration | No Comments

Configuring NSEL (Netflow Secure Event Logging) with Cisco ASA and Centos 6 server

Posted on:
March 8, 2013
Author:
Tomas Brandysky

These are the steps we need to do to make everything work together: Enable NetFlow feature on ASA box Install nfdump and nfsen software to collect the data from ASA Install and configure web server (eg. Apache) to make the graphs accessible via web browser 1. ASA setup ASA 5000 series comes with NetFlow version […]

Posted in ASA 5000 series, Cisco devices configuration, network administration software, Network Topology | No Comments

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