Ubuntu
linux package

  1. Bug #1743746
  2. Comment #0

Comment 0 for bug 1743746

Revision history for this message
James Page (james-page) wrote :

Under Linux 4.13 its not possible to configure GRE tunnel devices with a MTU larger than 1500; this impacts on Open vSwitch (which creates tunnel devices for GRE overlay networking) and the ip tools.

The kernel will error with:

  gre_sys: Invalid MTU 65000 requested, hw max 1500

The side effect of this is that if overlay networks are configured with high MTUs, the gre devices fragment the packets and networking is generally slow/broken.

This is resolved as part of the upcoming 4.15 kernel under:

  https://github.com/torvalds/linux/commit/cfddd4c33c254954927942599d299b3865743146