Command to Change MTU in Windows 2008 R2

Maximum transmission unit or MTU is by default 1500 for TCP/IP, however it needs to be adjusted
sometimes.
1‐
In order to change MTU in Windows 2008 R2, go to command prompt and typenetsh interface ipv4 show interfaces(press ENTER)You will get a table like this

Idx Met MTU State Name
--- ---------- ---------- ------------ ----------------------
1 50 4294967295 connected Loopback Pseudo-Interface 1
11 10 1500 connected NLB
12 10 1500 connected Public

From the table above we need the value of Idx which is basically id of our NIC connected to “Public” interface
2‐
Now type this command to set the MTU value to 1400 instead of 1500 

netsh interface ipv4 set subinterface "12" mtu=1400 store=persistent  (press ENTER)

If there is no error you will have an “OK” message.

3‐
Now re‐run the command to show interface details and you will see new value of MTU against “Public” Interfacenetsh interface ipv4 show interfaces
(press ENTER)

you will notice new value of MTU this time

Idx Met MTU State Name
--- ---------- ---------- ------------ -----------------------
1 50 4294967295 connected Loopback Pseudo-Interface 1
11 10 1500 connected NLB
12 10 1400 connected Public