As a part of the project, I needed to make replication of postgresql database to be available on different server for analization use.

Main database is being filled constantly with data while the replicated database needs to be accessible by several services in read-only mode on different segment of the network. Because of that and need of local backup direct connection of those services to main database wasn’t an option. So, plan for postgresql replication was needed. Also, as these two servers aren’t connected by secure network or any kind of VPN somehow they needed to have communication channel between them for transfering of the replication data solved – in a secure and least obtrusive way possible. Data status on the slave side doesn’t affect main server and there is possiblity of temporary out-of-syncs (in case of some network failure) which is good enough for the requirements of the project so replication can be done asynchonously. (more…)

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SSH – tips and tricks

Many people tend to think of SSH as a secure substitution for insecure telnet remote administration. While basically that is it’s main purpose (SSH is short for secure shell) what you can do with this tool is definitely not limited by only one task… (more…)

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Iptables port knocking – single port used

There are many things to make your computer more secure and sometimes something as simple as port knocking can do the trick.

Port knocking as technique is used for a long time now and many implementations are already out there although for my specific use none of them seemed to be appropriate.
For complete listing of these implementations please visit portknocking.org website. There you can also find a complete explanation of the methods as well as recommendations of use. (more…)

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