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Having some connection problems with my website, i found out that my server has a bigger problem. I installed it, with ubuntu 14.04. It is a cloud machine bought from a specific isp (ovh) but entirely configured by me, os included: i have full access to it. Since yesterday, i receive messages of connection timeout on sites like google so i tried 

 telnet google.it 80

It replies:

 Trying 2a00:1450:4007:80e::2003...
 Trying 216.58.208.227... 
 Connected to google.it.
 Escape character is '^]'.

But the second line gets printed after nearly a minute. It is extremely slow. And seemed to me strange even that the second line gets printed. So i did

 telnet 216.58.208.227 80

and the reply was immediate and fine.

Now, this means a dns problem, i guess. How can i investigate to know the real source for the issue, for sure? Considering the server stopped suddenly to work (till yesterday all was working fine) and that i leaved it untouched, can i say for certain that is my isp fault or it can be something went wrong on my machine, due to an external attack, for example?

Sasha Grievus
  • 233

1 Answers1

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This indicates an issue with the IPv6 address configuration.

Normally, if IPv6 is not configured at all, then IPv6 addresses aren't tried when you're trying to connect to any other host.

However, if IPv6 is, in fact, configured, but is configured incorrectly, then the problems as you describe will appear.

Solution:

You either have to disable IPv6 at all (make sure it is not configured at all), or make sure that if it is configured, then the configuration is applied correctly.

cnst
  • 14,646