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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.