PostgreSQL pg_upgradecluster

If the version of a PostgreSQL server changes, it is required to upgrade the version manually. This can e.g. happen, if you do a release upgrade of your Linux distribution. The below description explains how to use PostgreSQL pg_upgradecluster to upgrade PostgreSQL 9.6 from Debian Stretch (Debian 9) to PostgreSQL 11 of Debian Buster (Debian 10).

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build PgModeler from source

PGModeler ( is a nice tool to design your (PostgreSQL) database. It supports import from and export to a databases. Ubuntu 15.10 comes with a quite recent version but e.g. Debian does not provide it in the repository. In this post I explain howto build the application on Linux (tested on Debian 8) from source.

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Protecting servers with fail2ban – Apache HTTPd webserver

In the next part of the series, the protection of webservers is explained. In this example I use Apache HTTPd webserver. Similar configurations are also available for e.g. nginx. There are various reasons for protecting the webserver itself (webapplications installed will be described in on of the next posts). Attackers are e.g. scanning the server for vulnariblties or try to attack the server using invalid input.

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Protecting servers with fail2ban – protect ssh

As the next part of the series, the protection of the most common service SSH is described in this post. Almost every Linux based server will run a version of ssh daemon to be able to login from remote. In this post I will describe how to protect ssh using fail2ban.

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