Macrotone Blogs

Macrotone blogs upon Joomla, our products and other matters.

An IT professional with a wide experience of IT systems, specialising in Database Management and Security.

Mail ISO-8859-2 character sets

We recently received a report that the email fetching feature within our Joomla Issue Tracker component wasn’t handling the subject header and email body correctly for the ISO-8859-2 character set. This character set is used by a number of Eastern European countries, so we were interested in resolving the problem if we possibly could.

We tend to use the standard PHP imap routines and it was immediately obvious how we should handle the subject, but implementing a call to the imap_mime_header_decode method. This worked well and was a very quick fix.

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MariaDB and Joomla ?

MariaDBWe were looking at the possibilities of upgrading the version of MySQL we are using on out NAS system and were reminded of the existence of the MariaDB database as a possible alternative. Alternative because our NAS does not easily permit the upgrade of the MYSQL part of the system mainly because it is so tightly tied into the other features.

What is MariaDB one might ask. Well there is probably no better explanation that that upon the MariaDB web site.

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Handling Googlebot URL detected errors.

GoogleWe tend to use Google Webmaster Tools to monitor our main site and in particular the Crawl Errors that it detects.  Sometimes we are a little confused as to where the errors are coming from since the 'source' URL is sometimes the self same page indicated as in error, and others indicate pages where we fail to find the link referenced as in error.

That said it has proved generally useful and mostly they are trivial to fix.  What it has been difficult to discover, is a good reference guide to the topic of Search Engine Friendly URLs known as SEF. Whilst acknowledging that the subject of SEF can be quite involved, our searches have yet to reveal a good comprehensive article upon the best design and implementation mechanisms. It is even more difficult to discover a good guide to resolving problems. Having found nothing suitable we decided to create this post as a record of our investigations and perhaps act as a guide for others.

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ICANN looking to handle DNS namespace collision risks

I note from this article that a draft of a report (PDF) commissioned by ICANN and carried out by JAS (Joint Applicant Support) Global Advisors includes a series of recommendations — ranging from alerting network operators by returning 127.0.53.53 as an IP address to, in extreme conditions, killing a delegated second-level domain — to deal with the issue of traffic intended for internal network destinations ending up on the Internet via the Domain Name System.

Instead of the familiar 127.0.0.1 loopback address for localhost, the report suggests "127.0.53.53". Because the result is so unusual, it's likely to be flagged in logs and sysadmins who aren't aware of a name collision issue are likely to search online for information about the address problems.

"Numerous experiments performed by JAS confirmed that a wide range of application layer software logs something resembling a 'failed connection attempt to 127.0.53.53' which is the desired behavior. We also confirmed that all modern Microsoft, Linux, Apple, and BSD-derived operating systems correctly implement RFC 1122 (albeit with variations) and keep the traffic within the host system, not on the network," the report states.

MySQL and JSON data structures

mysqlHaving been working with JSON data structures recently our thoughts turned to how this could reasonably be handled by SQL queries in the production of items such as reports etc.  Leaving aside the question of how one would ‘know’ and handle the various constituents in the specific JSON object on a generic basis, we looked specifically at what was currently available.

Coming from a strong Oracle background we were familiar with the use of Java within the Oracle database and indeed have made use of it ourselves in the past, but our specific interest this time was MySQL and its use by Joomla, and we were not aware of any feature implementing Java with the MySQL database.

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Kunena – Administrator post delete clarification

kunenaOne observation we have made since using Kunena is that one is presented with an ‘Access Denied’ message if an attempt is made to reference a non-existent Forum topic/message. We wanted to investigate this further since we wanted  to get a 404 redirection defined such that the URL could be redirected either to a full ‘404’ page or an alternative Forum post.

We started out creating a new forum post which we then wanted to ‘delete’.  This led us to a different puzzle since our Forum administrator was unable to ‘delete’ the post.

Being a little puzzled about why our Kunena administrator couldn’t see an option to delete a post I have delved a little deeper to understand what was going on with specific checking on the ability to ‘delete’ posts.

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Oracle–Flashback Query

oracleWay back in 2001 Oracle announced Oracle9i with a new feature named ‘Flashback Query’. The implication was that Flashback technology would permit one to query past data, no matter how old it was days, weeks or even months old. In fact the actuality was very different since Flashback Query relied upon the undo information contained within the database Undo-Segments.

Later releases refined what was possible. It was named ‘Total Recall’ in Oracle 11g, and now goes by the name of ‘Flashback Data Archive’.  This recent blog goes into a little detail of the recent changes available in Oracle release 12c.

It is an easy read, but at the back of the mind one can’t help but think how much disk storage is required on a busy site to enable one to search back over long periods of time. The feature is useful, and is available ‘free-of-charge’ with all versions of Oracle 12c,  but at what cost in terms of system resources and performance?

Observation of Visitor Private IP addresses

It has been observed for some time that some of our site visitors, usually of the less desirable types have been ‘presenting’ Private IP addresses, as reported by our site protection software.

An IP address is considered private if the IP number falls within one of the IP address ranges reserved for private uses by Internet standards groups. These private IP address ranges exist:

10.0.0.0 through 10.255.255.255
169.254.0.0 through 169.254.255.255 (APIPA only)
172.16.0.0 through 172.31.255.255
192.168.0.0 through 192.168.255.255

Private IP addresses are typically used on local networks including home, school and business LANs including airports and hotels.

Devices with private IP addresses cannot (?) connect directly to the Internet. Likewise, computers outside the local network cannot connect directly to a device with a private IP. Instead, access to such devices must be brokered by a router or similar device that supports Network Address Translation (NAT). NAT hides the private IP numbers but can selectively transfer messages to these devices, affording a layer of security to the local network.

Standards groups created private IP addressing to prevent a shortage of public IP addresses available to Internet service providers and subscribers.

Despite the above, which is standard(?) Internet criteria, we have observed visitors using addresses in the 192.168 range for over a year.  However since the beginning of the month (February 2014) we have seen a large number of addresses in the 172.16 range as well.  Something has obviously changed as these should not be possible.

Searching on the web,  has not revealed any other site that reported the problem? Whilst not an issue for ourselves, since we do not use the IP address information for any purpose other than providing an assessment of where our visitors original from, it might well pose a problem  for other sites.  It is suspected that the only ‘real’ way to stop the practise would be to block the IP ranges, such that a visitor using an IP address from outside the local network, that has a value within the ranges, being effectively ‘blocked’ from accessing any information upon a site, although this should not, according to the criteria above be required.

Problems updating iTunes 11.1.4.62

apple logoJust received a update from Apple for iTunes, which I proceeded to install. Unfortunately it failed to install claiming it couldn’t restart Apple Mobile.

The error was 'Error 7 (Code 193)'

Tried a reinstall with the same results.

One suggestion seen on the web was to check the .Net installation, which I proceeded to do (version 4.5.1) and also checked that al .Net patched were applied, which they were.

Regretfully this didn’t not resolve the problem or make any difference at all.

In the end resorted to uninstalling all Apple products, including Quicktime. iTunes. Apple update service, Apple mobile etc., before performing a fresh reboot.

Now this time I could install the update successfully and it all works as before, picking up all existing music etc.

Why was the update so complicated?  I thought computing was supposed to be easy, not take up ones time performing pointless tasks.  Sarcastic smile

Website Features to avoid

Just read an interesting article on Mashable about a questionaire they did about annoying website features. I must admit many of them are all too familiar on a lot of sites one visits. I would however add one additional annoyance and that would be sites that do not support all of the common browsers - Firefox, IE, Chrome, Safari and Opera. No doubt you have your own particular pet hate as well.
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