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How to set the MTU size under Windows 7 ?

To manually set your Windows 7 MTU size, open command prompt as administrator and do the following:

1. Type: netsh int ipv4 show subinterface (this will show a list of network adapter names, and their current MTU values)

2. Type: netsh int ipv4 set subinterface "Local Area Connection" mtu=1480 store=persistent (where "Local Area Connection" is the name of the network adapter from the first command above, and 1480 is just a representation of the desired MTU size).

Network adapters are also listed under "Network Connections". For example, if the name of your network card under Network Connections is "Wireless Network Connection", and you'd like to set a MTU of 1500, you'd type:

netsh int ipv4 set subinterface "Wireless Network Connection" mtu=1500 store=persistent

3. Hit ENTER, reboot, and look at the output of "netsh int ipv4 show subinterface" again, the new MTU value that you set above should be retained.

The "network interface name" is viewable under "Network Conenctions"
A list of "network interface names" and their current MTU values is also available by typing the following in command prompt: netsh interface ipv4 show subinterface

  User Reviews/Comments:
by John P. Assai - 2010-11-11 22:24
I've tried to change my MTU to 1500 from cmd as administrator, it said "Ok",, then i'm going to TCP/IP Analyzer, and still MTU=1400
please tell me..
thanks in advance..
by anonymous - 2020-08-03 07:07
This article here will help you step by step, from Windows vista all the way to windows 10.

Does not involve cmd or powershell. And to anyone who mentions they attempted to change mtu via cmd, and check it to find out that the MTU is still the same?

Is because your MTU settings are actually disabled and auto negotiated.

This article here will solve your MTU Issues.
by Philip - 2020-08-07 11:12
Changing the Network adapter MTU can be done through the NIC settings, or through netsh. The Analyzer may show different results because your NIC is not directly connected to the Internet, it most often goes through a NAT router, then a Cable/DSL modem or an ONT, etc.

The SG TCP Analyzer shows the actual MTU that reaches our website, it is the MTU that your Cable or DSL modem uses. Setting your NIC MTU to a higher than 1500 jumbo frame means all packets will be repackaged by your NAT router before reaching the WAN side of the connection. For more specific information and questions, please use our forums.
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