Author Archives: George Valentin Voina

Blog Links: Server Backup with open source tools

By | February 8, 2017

There are lots of expensive backup tools that can be used to back-up an enterprise environment. HP and IBM are leaders of this market but the costs can go very high quickly. As an alternative one can choose some open-source backup suites that are on par with the commercial ones. Bacula Bacula is a very… Read More »

JavaEE: Caching costly data across a transaction with TransactionSynchronizationRegistry

By | February 8, 2017

Everybody knows that a database query is extremely costly in enterprise application and usually has the biggest impact in process time of a transaction. There are plenty of best practice rules a developer has to follow: 1. Retrieve as much data as possible in a single query, avoid to make a data retrieve from the… Read More »

Hibernate: Avoiding a “fake” exception: javax.persistence.TransactionRequiredException: Executing an update/delete query

By | October 21, 2017

I encountered some weird issue caused by the way Hibernate works. The exception messages returned by Hibernate are confusing as they are just a side-effect of the real issue. The code in question was something like that: In a manager bean we have the following: @Stateless(name = “ObjectManagerBean”, mappedName = “ObjectManagerBean/remote”) public class ObjectManagerBean …… Read More »

Blog Links: Web site security

By | November 11, 2016

I already had several posts related to constructing a secure website that can be released in the wild world-wide web. The following are several resources and links that will give a good idea on what one can do in order to secure a web site. First we need a way to analyse how secure our… Read More »

Blog Links: Hacking MSSQL, a strong case for implementing PCI

By | February 8, 2017

A fabulous piece from Rick Osgood on Hacking Microsoft SQL Server Without a Password. Using a man in the middle attach and ARP spoofing with a combination of free tools like Wireshark, Ettercap filters is able to hijack the SQL connection and execute arbitrary queries instead of the real queries. He manages even to create… Read More »

Blog Links: Resources for old WRT routers

By | September 1, 2016

I own several old WRT routers and they still can be used for having fun. The following is a list of resources I frequently use. Must have reference to WRTRouters How to Recover from a bad flash The main resources site for Open WRT Hardware list for Linksys WRT54G, WRT54GL and WRT54GS An interesting forum… Read More »

DB2: Debug db2 SQL exceptions

By | March 8, 2017

Sometimes the db2 exceptions are cryptic or hidden by the application layer. In this case the only way to find the db2 SQL exception is to investigate in db2 logs. First check the log level setup in the Database Manager Configuration. Log in as the user under which db2 instance runs, in my case db2inst1.… Read More »

EdgeRouter: Force add the default routes to the load balanced WAN interfaces

By | August 26, 2016

An EdgeRouter firmware update from 1.8.5 to 1.9 broke my L2TP based VPN. After the update my l2tp connection to local subnets was no longer working. Note that I have a load balancing setup with eth0 and eth1 being the load balanced WAN interfaces. It seems that due to the changes done for the l2tp… Read More »

Data Center: Add EdgeRouter logs to Security Onion

By | November 10, 2016

After seting up Security Onion as my home data center IDS (see https://blog.voina.fr/data-center-ids-solution-using-security-onion/) I started to integrate monitoring of other resources to it. The first idea was to add the monitoring of my EdgeMax routers. Security Onion has a syslog-ng service that is able to receive client syslog data. Then we can visualize this data… Read More »