Professional Development Workshops,
Technology Training & Consultancy

In Hanoi, Vietnam

It all comes down to DNS.

posted Oct 14, 2016, 9:30 PM by Heidi Hendry

Are you having problems with your Vietnamese home or office internet? Me too! And I work in this field, and end up tearing my hair in frustration, because I know how easy it is to fix. Unfortunately, many Vietnam Internet Service Providers (ISP) have unreliable DNS servers. (see here: ).

What is DNS? Well, DNS servers translate your web address request
into the IP address, which is how computers understand websites = NB. I know that I have over-simplified this completely!

The DNS servers that are listed in your modem will either be invisible to you, or hard-coded as something like
When these are unreliable, you will get the common error on your website of "dns_probe_finished_no_internet" or something similar.

Unfortunately, most technicians here in Vietnam use the workaround of entering the Google Public DNS servers of and, either on your modem or on your computer. The problem with doing this, is that those DNS servers are in the USA. So when the undersea cables go down, your home or office internet connection slows to a crawl, as all the DNS translations are going to the USA and back again.

And so you call the ISP again, and say "my internet is slow!". And so they come out and change your DNS servers back to default, which solves the speed problem, but then the next day their unreliable DNS server goes down.

You call them out again, and by this time the undersea cable is fixed enough, so they put Google DNS back in.
And then the undersea cable breaks... do you see where I'm going with this?
Around and around in circles.

So, how to solve this?

Ideally, your ISP will fix their DNS servers, but being a non Vietnamese speaker, they won't listen to me when I try to explain to them the problem. But if you can speak Vietnamese, then show them and maybe they will see where their DNS server is in regards to reliability .and fix it (<sarcasm>because everything is so logical here!</sarcasm>)

But, since that is an unlikely scenario, instead, make the technician put 100% reliable Vietnamese DNS servers into your modem. Again, show them this page, and find your ISP on there, and find their servers that are 100% reliable and put those ones there.

So, again, for example, I am with VNPT Hanoi and so the DNS servers that I am testing are: and

You can actually do this yourself if you have the login & password to your modem. You have to put them in the LAN DHCP settings area.

Time will tell whether this will work perfectly, and I am sure that there is still censorship happening on these servers too. And when that happens, I'll switch back to Google Public DNS servers to get onto Facebook.

The "things" you buy when you buy a "website"

posted Jul 7, 2016, 5:43 PM by Heidi Hendry

Let me explain...
When you buy a "website" or a "domain" from someone like CrazyDomains (a Registrar) usually you buy a bundle which includes:
Domain registration
DNS hosting
Website hosting.

Domain Registration: Purchase the domain so that no one else can buy it. Analogy: you bought a shop name but not the land or the building to put it on
Website hosting: Purchase the storage on the webserver to put your website files. Analogy: you bought a building to put the shop in, but there's no road to it.
DNS hosting: Purchase the right to put the domain on DNS servers so that people can find it. Analogy: you buy the road so that people can get to your building.
Website: Actually the website files. Analogy:  the shop fittings to make it attractive to visitors.

It is possible to buy these separately and sometimes you can get a cheaper deal if you do. But it's usually more convenient to have them all handled by the same company.
The other aspect of this is that registration and hosting expiry can differ, so it's possible to buy a domain for 1 year, and a website for 5 years, not realising that the domain has to be renewed every year.

Where I see messes, is when someone has asked their tech friend to help them out, and then later they ask me to help them because something has changed.

Sometimes this can get trickier because the tech friend has registered the domain, dns or website under their own name, and not the true owner's name. Domain transfer is a complicated business requiring proof of business ownership and lots of to-ing and fro-ing with the Registrar.

If your website hosting, domain or DNS is a mess, then contact me!

Wireless pain in your workplace?

posted Apr 9, 2016, 8:35 AM by Heidi Hendry   [ updated Apr 9, 2016, 10:23 PM ]

You have staff members complaining about the slow wireless? 

Or customers who say that the "internet" wasn't working.

It seems that here in Hanoi, the "solution" is to install another wireless access point.
But that's usually making the problem worse.

What is really going on?

Unfortunately, most of the wireless access points (WAPs) that I've seen here in cafes and businesses are cheap consumer-grade devices, as that is primarily what is easily and cheaply available.
The problem with using consumer-grade devices is that they are not designed for the amount of network traffic that a business-grade device handles.
Another problem can include only having the 2.4Ghz wireless frequency, instead of also offering the 5GHz wireless frequency.. 
The 2.4GHz frequency has a lot of interference on it which can slow the network traffic. Interference on the 2.4Ghz frequency comes from devices like cordless phones and microwaves.

And, the main interference is too many devices. If your staff have all their smartphones on the wireless network, then those smartphones are creating a lot of network traffic as well. 
And if your neighbours know your wireless password, then they are creating extra traffic as well.

And then there's malware. Malware, which you might know as "viruses" or "trojans", is "malicious software" is a common network traffic hog. 
Another reason to put your guest devices and smartphones onto a guest wireless network.

Some simple steps are:
1. Upgrade your devices
Wireless access points are available that will run wireless networks on both the 2.4GHz and 5GHz frequencies. Read more on the two frequencies here.
Also, there are WAPs that will run a guest network.
Look for business-grade wireless access points, like UniFi long range access points or HP Aruba wireless access points. In Vietnam, we have limited choice, so if TP-Link and D-Link are all you can find, then look for business-grade products.

2. Setup a guest wireless network
Get your guest devices and staff smartphones off your primary work network. You can do this with upgraded devices, or add some new WAPs.

3. Run a wireless heat map check
Using software like Ekahu HeatMapper, look for the "cold" spots in your wireless coverage.

4. Check the channels in use
Your wireless is competing with the other nearby wireless networks, and the best way to minimise the interference from those other networks is to ensure your devices are using different channels.
Use Acrylic WiFi scanner to find the channels the other networks are using, and read this article on channel overlaps

5. Get rid of malware.
Devices on your network should all be regularly checked for malware. Either with antivirus software, set to scan regularly, or regular one-off checks with a program like Malwarebytes or Trend Micro's HouseCall.
Professional Development Workshops,
Technology Training & Consultancy
In Hanoi, Vietnam

New Google Forms - Responses Charts

posted Mar 29, 2016, 12:48 AM by Heidi Hendry   [ updated Mar 29, 2016, 12:50 AM ]

Google Forms is revamped, and the New Google Forms has some cool new features.
Well, "cool" if you are a maths geek like me. New Google Forms gives you a Responses page with some lovely graphs automatically generated.
I went hunting to see if someone else out there had documented what type of charts/graphs appear for each type of question. And I couldn't find anything, so here you are:

Form Question Type
Chart Type
When to Use
Drop-down list Pie Chart What proportion of all respondents gave a particular answer
Multiple Choice Pie Chart What proportion of all respondents gave a particular answer
Linear Scale Column chart How many of each answer is there?
Checkboxes Bar Chart How many of each answer is there?
Multiple Choice Grid All Answers Column Chart How many of each answer is there, and how do they compare to each other question (row)

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