Hey there, I have set my MTU setting in Network to MTU = 9000. Now I want to reset it as I learnt this setting is not compabtible with my network.
After resetting it to default, the settings are not saved; I still see the MTU=9000 as set before. Any idea? Firmware is QTS 5.2.6.3195
Any help appreciated 
Is your network adapter part of a virtual switch? If it is, I think you have to remove it from the virtual switch in order to change the MTU. I just tried changing it on mine (mine is 1500 and I wanted to set it to 9000), but it won’t take. I make the change and nothing happens. Mine is part of a virtual switch.
Hi @NA9D
Thanks for your reply. InDeed my NIC is part of virtual switch. So that means I would have to remove the virtual switch completely, set the correct MTU, reconfigure my virtual network? But I understood you did not perform theses steps on your side ?
I have not performed those steps. While I would like to use a Jumbo Frame MTU everywhere in my network, for some reason, some of the NICs on my computers don’t support it. So if it’s at 1500 it’s OK. For you, it’s worse going the other way when packets that are too large can’t get through the NICs running smaller MTUs…
We’ve confirmed this is a software issue, and it will be fixed in a future version. Thanks for reporting it!
1 Like
Sounds good 
Any timeline already?
Update from my side: With firmware QTS 5.2.7.3256 the MTU is now changeable and the changes to to e.g. MTU=1500 are persistent.
1 Like