VMware certification exams – 25% discounts (2015 offer)

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Igreenf you’re in the market to take a VMware certification exam, there’s some good news – provided you’re quick. For the next couple of days (while VMworld US is running, August 30th-4th September 2015) you can book VCP and VCAP/VCIX exams at a cool 25% offeven if you’re not at the conference! Like last year it’s only 25% (in earlier years it was 50% and if you’re attending the conference in person it still is) but every little helps.

Sadly the period of time to actually sit the exam has been shortened (see below) compared to previous years but if you want to blitz multiple certification tracks you can – you’re not limited to just one.

The codes you need to register with are;

  • VCPWDF25 – for the VCP exams (VCP-DCV, VCP-DT, VCP-Cloud/CMA, VCP-NV)
  • VCPADWDF25 – for the VCAP exams (VCAP-DCA, VCAP-DCD, VCIX-NV)


  • You MUST book the exam while VMworld US is running, 30th August to 4th September 2015. You don’t have to be attending the conference, it’s just the period of time the offer is valid.
  • You MUST take the exam by October 15th, 2015

What are you waiting for? Head over to VMware Certification and get registered certification junkies!


Physical patching – down the wormhole with a borescope!

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Summary: Virtualised environments don’t need physical patching. My home, sadly, does but a cheap USB borescope made the job simpler and quicker.

This week I’ve been busy setting up my home office ready for Monday when I start my new job. One of the most time consuming tasks has been running network cable (CAT6) for connectivity – my previous experience with PowerLine technology was somewhat mixed and I decided that hardwired was the way to go now that I’m working from home all day every day. Unfortunately the layout of my house meant a couple of long runs (one 70m, one only about 20m) through multiple walls and floors/ceilings. Some parts of the cable run were relatively easy but others involved going through areas where I had limited visibility and access (ie behind masonry walls and through floorspaces) and didn’t want to make a mess (ie cut access panels or chase cables into plaster).

electrician-rodsEnter the DBPOWER® USB HD Borescope (what is a borescope?) which I bought via Amazon for a mere £18. This nifty geek tool lets you put a camera inside small spaces and see the output on a computer screen in real time, and when combined with a set of electrician’s wiring rods (£8 from Amazon) it was great for threading cable. I still had to drill holes through both the floor and ceiling (about 16mm to allow the ethernet connector – I was being lazy and not crimping my own) but navigating around obstructions, finding the exit hole, and pushing the cable through would not have been possible without this kit.

It’s wasn’t all smooth sailing. The borescope’s magnified view makes it pretty difficult to recognise what you’re looking at – the built in lighting can help but the focus jumps around in dark areas making it challenging. The electrician’s rods are good for pushing in a straight line (and with some flex) but the borescope I bought didn’t have a gooseneck (some do, though costs generally go up) so directing the camera inside floorspaces was pretty difficult.

Still for a total cost of £25 I managed to run my cables and avoided more hours spent on DIY making good, plus it appealed to my geek tendencies. A good job well done!

Chromecast causing wifi interference – resolved

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Summary: I’ve found Google’s Chromecast to be a great streaming device but in rare cases it can misbehave and cause wireless access issues.

I bought my first Chromecast the day they were released in the UK (March 18th 2014), totally by chance, and I’m a big fan. Once setup they’re simple enough to use that my 2yr old son can now use a tablet to power on our TV and watch a program of his choosing via BBC iPlayer or Plex without any help from me – and that’s something my in-laws can’t manage. I’m not sure it’s socially a good thing but at least the technology works!

Chromecast wifi analyzerHowever I have noted a few issues, notably with their use of wifi. When you first plug in the Chromecast it’s in ‘master’ mode which means it acts as an access point, thus allowing you to join its wireless network with a tablet and configure it (and also opening up at least one vulnerability). Once the initial setup is complete however it’s supposed to go into ‘managed’ mode which means it should stop being an access point and act only as a wireless client but mine was still intermittently acting as an AP and therefore causing interference, as seen by Wifi Analyser (highly recommended by the way). In my case (and for others too) I saw additional wifi signals, always on the same channel as my home wifi, and the signal strength was greater than my home wifi when I was near the Chromecast. The Chromecasts didn’t broadcast an SSID (it showed as ‘?’ in Wifi Analyser) with a MAC address starting in fa:86:ca, which belongs to Google (although none of the OUI lookup databases seemed to know it).

This useful article about how Chromecast uses the Wifi network, including packet captures, goes into some possible causes although it’s been 18 months since the Chromecast was released and firmware updates may have resolved some issues mentioned.

How do I fix it?

The fix, at least for me, was a factory reset of the Chromecast – hardly worth of a blogpost! However I’d ‘reset’ mine several times by simply going into the Chromecast utility on an iPad (or Android tablet) and after a reboot I’d go through the setup again (inputting wireless password, naming the device etc) and that DIDN’T fix the issue. A factory reset can be done by holding down the power button on the Chromecast for 25 seconds until the light on the device flashes or via the Chromecast app (detailed walkthrough here).

It’s also worth checking that it’s running the latest firmware (31432 as of May 22nd 2015, according to Wikipedia) – it should update automatically (and in fact you can’t stop it doing so which isn’t ideal) but sometimes a factory reset gives it the kick up the proverbial it needs to update. If you need help the official Google Chromecast forum is a good place to start as is the online troubleshooting wizard.


A new challenge…joining VMware

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Summary: An unexpected career change!

I’m excited to announce that from late July I’m going to be joining VMware as a Senior Technical Marketing Engineer.  The role will be a change compared to all of my previous roles which have entailed operating infrastructure as an end user and more recently as a service provider whereas I’ll now be focused on marketing for a vendor, albeit from a technical perspective. I’m excited because my skillset has gravitated around VMware/virtualisation/cloud for quite a few years and this role will require knowledge of areas I’ve not previously been responsible for, in particular the 3rd platform (think cloud native applications, containers etc) and VMware’s competition.   I think it’s an interesting time to join VMware as the world of ‘cloud native applications’ finally seems to be meeting the enterprise infrastructure world via technologies like Docker and the relationship with Pivotal is becoming more, well, pivotal! Time will tell if VMware (or I) live up to expectations….my imposter syndrome is at an all time high right now. :-)

This job is only possible for me, living as I do on a remote island in the English channel, because I’ll be working remotely – which is a first for me and something I’m both looking forward to and concerned about. I’ve always enjoyed the social interaction in an office environment and building relationships remotely is a different experience – though one I think social media has prepared me well for. Time to soak up those home working/office blogposts!

As with everything in life there’s a compromise and obviously I’m compromising my independent viewpoint. It’s always been a luxury to have (almost) complete freedom of speech without company politics being a concern – as an end user I was largely free to say exactly what I felt, good or bad. However hard I try I don’t believe I can be ‘independent’ when all my focus (and livelihood) depends on improving VMware products – we all have biases – so blog disclaimer or not you’ll have to interpret anything I say through the lens of a vendor employee. To my friends who work for other vendors – let’s make sure our choice of employer doesn’t affect our relationship!

I still intend to engage fully with the community. It keeps me honest, keeps me learning, and is one of the most enjoyable parts of my career, even if I can no longer attend TechFieldDay events. If I can walk the line between corporate expectations and my personal thoughts, which very few seem to manage, I’ll be a happy man.

I’d like to take this opportunity to thank Sure International for a great year – if you happen to be in the Channel Islands you should check our their cloud solutions! Thanks for reading and hopefully this next step in my career will lead to more great content in the future.




WordPress connectivity issues (Jetpack and XML-RPC failure)

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Summary: Some WordPress features can be abused and are therefore locked down by hosting companies. My hosting company recently made changes to their security which broke features I use for my blog. The fix, once identified, was quick and easy.

I’ve been blogging for around five years and am impressed with how easy and reliable WordPress has been over that time, despite constant updates. Earlier this week however I logged into my WordPress console and was greeted by an innocuous looking error message;

Wordpress error


As suggested I tried disconnecting Jetpack and reconnecting but that didn’t work – Jetpack refused to reconnect and gave an error message saying my site wasn’t publicly accessible;

Wordpress error2

I tested the site which seemed to be available and working as expected. Diving a bit deeper I read into the plugin connectivity requirements and found that Jetpack (among others) relies on the XML-RPC protocol, which is now enabled by default in WordPress since v3.5. At a basic level you can test this by putting a simple URL in a browser – http://yourWordpressSite/xmlrpc.php – and it’ll return the single line ‘XML-RPC server accepts POST requests only‘. This worked fine for me but knowing that the mobile (iOS and Android) WordPress app used XML-RPC I tried those and found they weren’t working. Hmm.

At this point I logged a call with WordPress (and generated a debug bundle) who were quick to confirm that from their perspective the website wasn’t responding to a ‘curl’ request (different to the basic test above) and they advised talking to my hosting company. I’d recently upgraded WordPress to v4.2 so suspected that might be related and in my opinion it seemed unlikely that the hosting company had locked down such a popular feature, certainly without notification, but I logged a call with them just to be sure. I was wrong and WordPress support were right! My hosting company (EvoHosting, highly recommended) advised me that due to DDoS attacks using aspects of the XML-RPC functionality they’d been forced to restrict it.

The fix was to install an additional WordPress plugin which limits the XML-RPC functionality (it stops XML-RPC pingbacks) but still allows the more popular features typically used by mobile WordPress apps and some plugins like Jetpack. With this installed they were able to whitelist my site and I was able to reconnect Jetpack and get my mobile apps working again. Obviously this fix won’t work for everyone as it depends on how restrictive your hosting company are – they may block XML-RPC completely, in which case you’ll have to plead your case. WordPress have a list of recommended hosting companies who all allow allow this functionality.

NOTE: I also believe this was the root cause of my the Jetpack Publicize issue whereby LinkedIn ‘needed refreshing’ constantly. Two birds with one stone…

Morale of the story – just because you work in IT don’t assume you know more than support teams. Some of them are very good and know their stuff! Guilty. :-)

Further Reading

WordPress XML-RPC PingBack Vulnerability Analysis