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How to Change MTU Value on Windows (XP, Vista, 7 and 8)

Admin
Nov 08, 2014
Aug 23, 2017
7 Comments
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Things to Consider:

Before you begin, please make sure that:

  • You have a working internet connection
  • Connected VPN on Windows supported device
  • A Premium PureVPN account (if you haven’t bought it yet, click here to buy)

To set the best MTU value and optimize VPN speed, please perform the following steps:

First connect VPN. If you are using PureVPN Client then it will automatically create VPN connection named PureVPN. If you created the connection manually then it will appear in Step 3 and you need to modify the command given in Step 4.

1 Open “Command Prompt“. Make sure that you have Admin privileges.

On Windows XP, Vista and 7, Click on Start button and click on “Run“, type “cmd” and click “OK“.

On Windows 8, right click at bottom left corner and select “Command Prompt (Admin)”.

2Type the below command and hit enter to check current MTU value . Note down the current MTU value in case you want to revert changes.

netsh interface ipv4 show subinterfaces

3 Type the command below and hit enter.

ping www.google.com -f -l 1500

If the reply you get is “Packet needs to be fragmented but DF set.”, then you have to try a lower MTU value. Keep decreasing the value by 10, i.e. 1490, 1480, 1470 until you get a successful reply. Start increasing the MTU value with small increments after you get a successful reply. Eventually, you will arrive on a value on which packets will not fragment, add 28 to that value (IP / ICMP headers).For instance, if you got the last successful reply on 1470, then add 28 to it, 1470+28 = 1498.

4This number is your MTU value.

If you are using a LAN connection, then type the following command:

netsh interface ipv4 set subinterface PureVPN mtu=1498 store=persistent

OR

netsh interface ipv4 set subinterface “PureVPN” mtu=1498 store=persistent

where PureVPN is the VPN Connection name.

Recommended:

If some websites are not loading while connected to VPN then please try MTU 1200

netsh interface ipv4 set subinterface PureVPN mtu=1200 store=persistent

OR

netsh interface ipv4 set subinterface “PureVPN” mtu=1200 store=persistent

Please use the comment box for your suggestions & feedback. For additional help, please submit support ticket with errors and screen shots (if possible) or contact our 24/7 live chat.

 

 

 

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Comments (7 )

7 Comments

  1. PureVPN Team says:

    Hi Somal,

    We are sorry for the inconvenience. It seems you are not typing correct command, We would request you not to copy it but rather type the command manually. Try this and let us know if it works!

  2. Somal Chaudhary says:

    Hello! The last command does not work for me. I am using a WiFi connection. I get this error:

    “The filename, directory name or volume label syntax is incorrect.”

    Your help would be appreciated!

  3. PureVPN Team says:

    Hi Steven,

    Thanks for reaching out to us. Well, you can use the same command it should work fine.

    Let us know if we can help you with anything else!

  4. Steven says:

    How if im using wifi connection ? whats the command ?

  5. 거스 Gus says:

    Hi! When lowering the MTU value, as of 1472 or lower I get a “request timed out” response, but at 1473 I still get the “fragmented” response. Any tips? Thanks!

  6. Sensie says:

    Amazing .. very helpful information not only with PureVPN but will my work as Network Engineer 🙂
    i know how to change it on the Routers/Switches Now on Computers Too ^_^