How to remove DNS Poisoning

To find the address to a site, your computer asks another computer (a so called Domain Name Server or DNS) which stores this information. If this DNS gives your computer the wrong addresses to some sites, it is known as DNS poisoning.

When connected to PandaPow your computer is given the correct addresses to existing sites, but your computer may still be storing some old poisoned addresses that needs to be removed. Here is how to do this:

 

Windows

  • In the Start Menu, locate the Command Prompt menu item usually found in the AccessoriesRight click on the Command Prompt menu item and select Run as Administrator.
  • In the command prompt window type the following command:

ipconfig /flushdns

  • If the problem persists. Type the following 2 commands:

net stop dnscache

net start dnscache

  • If the above doesn’t help, your problem might be unrelated to DSN poisoning. You should instead try changing the DNS settings as described here: How to change DNS on Windows

 

Android

Usually Android clears the dns-cache automatically quite regularly, so if opening a website in the browser fails you may just want to wait a few moments and try again.

Unfortunately some apps, like the Facebook and Twitter apps, seems to keep poisoned DNS information for quite a long time. The only workaround we’ve found so far has been to wait, while keeping PandaPow connected, and then restart the app. If you don’t want to wait we recommend accessing these sites via the browser instead of the apps.

If you are unsure if your problems are due to bad DNS information you can try to ‘ping’ the website in question. Use, for instance, the app PingUp to test whether the site can be reached or not.

Link to PingUp in Android Market

 

Mac OS X

  1. Hit ⌘+ Space, then type “Terminal and hit Enter.
  2. Do one of the following, depending on your OS version. To check your Mac version, Click on your Apple menu, then select About this Mac.

 

  • On Snow Leopard (Mac OS X 10.6.x), type:
    dscacheutil -flushcache and press the Enter key.

 

  • On Lion (Mac OS X 10.7 and 10.8), type:
    sudo killall -HUP mDNSResponder and press the Enter key.

 

  • On Mavericks (Mac OS X 10.9), type:
    dscacheutil -flushcache;sudo killall -HUP mDNSResponder and press the Enter key.

 

  • On Yosemite (Mac OS X 10.10, 10.10.1, 10.10.2, 10.10.3), type:
    sudo discoveryutil mdnsflushcache and press the Enter key.

 

  • On Yosemite (Mac OS X 10.10.4 and 10.10.5), type:
    sudo dscacheutil -flushcache;sudo killall -HUP mDNSResponder;say cache flushed and press the Enter key.

 

  • On El Capitan (Mac OS X 10.11) and Sierra (Mac OS X 10.12), type:
    sudo killall -HUP mDNSResponder and press the Enter key.

 

NOTE: When typing in your Mac password, you won’t be able to see what is being typed. If there is no error, then the flush is successful.

If the problem remains, please verify your DNS settings. If you type the following in the terminal:

scutil --dns

It should display a number of “resolvers” where the first one should have the following entries:

nameserver[0] : 8.8.8.8
nameserver[1] : 8.8.4.4

If not, you might want to go ahead and set the DNS settings manually as described here: how to change DNS under OS X

 

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