Re: [Openvpn-devel] Re: New beta available + progress update

[Matthias A. <ma+...@dt...>]

On Thu, 17 Apr 2003, James Yonan wrote:

> The nice part about a radio link is that it is probably under your control,
> meaning that you can ensure that ICMPs get properly passed.  This allows path
> MTU discovery to work and therefore solves a lot of the harder problems.

Well,  at least for the bits that crossed a Linux 2.2 masquerade
router...

> In this case, the FRAGMENT_ENABLE code would take the Path MTU hint from the
> OS rather than trying to figure it out empirically by trial-and-error.  The
> current FRAGMENT_ENABLE code knows how to get the PMTU from Linux, but still
> needs code for other OSes.

For FreeBSD, apparently the routing table has to be queried for the MTU
-- unless someone comes up with better information. NetBSD has an
IP_RETURNMTU ioctl, I'm unsure about other systems. Seems to be
non-standard :-/