This is a companion discussion topic for the original entry at https://linuxconfig.org/how-to-enable-jumbo-frames-in-linux
Although large MTUs are nice, devices with smaller MTUs will not “break them up into smaller sizes as needed” without a gateway that bridges the exact MTU sizes on either side (i.e. a 1500 byte MTU interface and a 9000 byte MTU interface). You can get away with this if all of your packets are small, like SSH but if you try to send a 1501 byte MTU packet to an interface with a 1500 byte MTU the interface will just drop the packet as corrupt.
Bruce Ferrell -> Schism
Actually it depends on the DF bit in the header and a thing called “path mtu discovery”. IF DF is set, you’re correct. If it is not, you are incorrect.
EDA -> Bruce Ferrell
– haven’t played with frame setting for years. Question: how would one force / set the DF in the header (if such is possible).