MTU Probing for Linux
John Heffner <email@example.com>
This work has been pulled into the mainline Linux kernel, and is now available in versions 2.6.17 and greater. This page is now obsolete.
This is an implementation of TCP Packetization Layer Path MTU Discovery (current internet-draft). The patches are against Linus's development tree, so they may need minor fixups if applied against official releases. It currently has some debugging printk's, and does not fully implement the spec, but I beleive it more or less works. (I've been running it myself without too much trouble.)
I'm very interested in any feedback on areas where it does not work well. I am actively working on this patch and I have a number of TODO items. Keep checking back for new versions.
December 6, 2005: Version 06 for 2.6.15-rc4.
November 30, 2005: Version 05 for 2.6.15-rc2.
March 31, 2005: Version 04 for 2.6.12-rc1.
March 30, 2005: Version 03 for 2.6.12-rc1.
March 21, 2005: Version 02 for 2.6.12-rc1.
March 6, 2005: Version 01 for 2.6.11.
PMSSD, an old patch for 2.4 predating the PLPMTUD internet draft.
Kevin Lahey's NetBSD implementation, from approximately the same time.