Windows 8.1 Mtu resets

[schwatzz]

I run command prompt as administrator and input the correct settings as it it says "ok" after I change the mtu from 1500 to 1492. However when I restart my computer and check the mtu setting again, it has reverted back to 1500 for my wireless connection. I can get it to work on my Windows 7 computer with no issues. My connection is pppoe and my router mtu is set to 1492 but I would like to have my Windows 8.1 computer set to 1492 as well.

 

[Astroninjaben]

Hello

You can set the mtu back to 1492 with
netsh interface ipv4 set subinterface "X" mtu=1482 store=persistent

Where X is the subinterface #

 

[schwatzz]

Hey thanks for the reply. I ran what you suggested in command prompt. It managed to save the mtu settings for ethernet and loop back however, it did not save for my Wi-Fi connection after restarting my computer. Is it possible that Windows 8 attempts to control the mtu settings through path mtu? It is peculiar since I ping a site for example ping google.ca -f -l 1464 and I get a reply on that and when I put in 1465 it is fragmented, so adding 28 for overhead would make it 1492.

 

[Astroninjaben]

Hmm, strange, have you tried TPC Optimizer?

If your FIOS connection is older, it will use PPP encapsulation (and get an IP via PPP) instead of the newer method of Ethernet. PPP encapsulation requires your MTU to be down at 1492, because the PPP header adds an extra 8 bytes to the packet, which would [normally] put it up to 1500, then your packet would be fragmented on its way out of the router (fragmentation = more latency)

If you put your MTU up to 1500, you might see poorer performance because your router has to break your 1500byte packets into a 1492 byte packet, and one additional tiny packet.

 

[schwatzz]

Hmm well it appears the when I changed the MTU for the subinterface "ethernet" it remained at 1492 after the reboot however the subint "Wi-Fi" will revert back to 1500 instead of the desired 1492. There must be a setting that is restoring the default of 1500. I think I'll try to directly modify the registry and see if it will save.

 

[Astroninjaben]

Hmm well it appears the when I changed the MTU for the subinterface "ethernet" it remained at 1492 after the reboot however the subint "Wi-Fi" will revert back to 1500 instead of the desired 1492. There must be a setting that is restoring the default of 1500. I think I'll try to directly modify the registry and see if it will save.

Yeah, sometimes it's just a matter of deleting a key or changing a value,

Good luck

 

[Cooped]

Hmm well it appears the when I changed the MTU for the subinterface "ethernet" it remained at 1492 after the reboot however the subint "Wi-Fi" will revert back to 1500 instead of the desired 1492. There must be a setting that is restoring the default of 1500. I think I'll try to directly modify the registry and see if it will save.

schwatzz, did you ever get any success with setting the MTU? trying to solve the same issue as you have described but finding it hard to sort out?

 

[schwatzz]

Hmm well it appears the when I changed the MTU for the subinterface "ethernet" it remained at 1492 after the reboot however the subint "Wi-Fi" will revert back to 1500 instead of the desired 1492. There must be a setting that is restoring the default of 1500. I think I'll try to directly modify the registry and see if it will save.

schwatzz, did you ever get any success with setting the MTU? trying to solve the same issue as you have described but finding it hard to sort out?

I was never able to find a solution. I tried some programs that change the MTU for you but those never worked. I might try to find a solution for later. For now, the MTU remaining at 1500 isn't causing any noticeable problems.

 

[Cooped]

Hmm well it appears the when I changed the MTU for the subinterface "ethernet" it remained at 1492 after the reboot however the subint "Wi-Fi" will revert back to 1500 instead of the desired 1492. There must be a setting that is restoring the default of 1500. I think I'll try to directly modify the registry and see if it will save.

schwatzz, did you ever get any success with setting the MTU? trying to solve the same issue as you have described but finding it hard to sort out?

I was never able to find a solution. I tried some programs that change the MTU for you but those never worked. I might try to find a solution for later. For now, the MTU remaining at 1500 isn't causing any noticeable problems.

Thanks mate, I'm launching a case with MS as I do need to change the MTU for WiFi in our corporate and as with what you have said, I can change it once, but on reboot it wipes back to 1500.. If I get anything back, I will post.

thanks