Jumbo Frames on DIR-655

I am trying to set up jumbo frames on my gigabit home LAN but no luck so far.

My setup is:

• D-Link DIR-655 router, HW Revision A3, Firmware 1.21 EU
• Synology DS107+, Firmware 3.0-1337
• Laptop w/ Win7 x64, external PCIx NIC managed by "Generic Marvel Yukon 88E8053 based Ethernet Controller"

The router is supposed to support jumbo frames but doesn't feature any relevant setting. I set the Jumbo Packet value to 9000 on both the NIC and the Synobox but it doesn't work, ping -f -l 8972 says "Packet needs to be fragmented but DF set".

Is there any other setting I overlooked, the DIR-655 doesn't actually support jumbo frames, or what else could be the problem?

Solution 1:

I can get 4k Jumbo frames to work correctly with this model not 9k. I had to manually set jumbo frame size in my nics as well.