Packet needs to be fragmented but df set jumbo frames. May 19, 2023 · The ping response will show “Packet needs to be fragmented but DF set” message which indicates the point where fragmentation is required. Oct 10, 2010 · To enable Jumbo Frames, please follow the guide below. If your router is set to 1500 bytes, try hardcoding it to a smaller size. To verify this has worked you can use ping in windows with the -l flag to set the packet size, and the -f flag to set Don't Fragment flag in the packet. In this tutorial let us check the reason and solution for this error message. Nov 23, 2013 · While testing the correct MTU size of your current network, sometimes you may receive the error message " Packet needs to be fragmented but DF set ". Oct 19, 2014 · Yes, it looks like the path between the NAS and the PC is limited to normal ethernet (1500 byte MTU). Enabling Jumbo Frames means allowing a larger Maximum Transmission Unit (MTU), usually by setting the MTU to 9000. Hardcode your clients with a smaller MTU size. Using ping without options will use 74 bytes packets on the wire (14 byte Ethernet + 20 byte IP + 40 byte ICMP Payload). Or upgrade your routers and switches to support JF. Make sure your routers do not drop ICMP "Destination Unreachable-Fragmentation Needed and DF Set" messages. (Before carrying out these changes, please ensure that your drivers are up to date, if they are not, you may experience performance issues) Sep 11, 2025 · Here are some steps you can take when dealing with an MTU issue. . For best performance on your existing network turn Jumbo Frames off everywhere. exzmu bnku ejcdo avtqm qvkdk dwfcsw rsq mdotw nfiegpj edte