On Tuesday, 13 April 2021 13:14:48 BST Harald Welte wrote:
Hi Keith,
On Tue, Apr 13, 2021 at 11:10:18AM +0100, Keith A. Milner wrote:
However, if I change to using Kernel GTP, by changing the gtpu-mode to "kernel-gtp", traffic will not route (and, yes, I have done modprobe gtp). After some exploration, it appears the tun device is being created with an MTU of zero which then, cannot pass traffic:
I think this one is fixed in https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/dr ivers/net?id=e21eb3a065a2d90ee3bb06cc2e77acad403ec7cd but "of course" Debian 10 is using a too old kernel to contain that fix.
Ah, missed that. Thanks Harald.
You could ask Debian if they'd back-port it to the stable kernel?
It's not that big of an issue for me, as this is just for some testing. I was mainly concerned I had missed some configuration somewhere. As I can use the ipup-script this will work for me.
We would certainly also be happy to accept a patch mentioning this in the user manual, or a patch that makes osmo-ggsn check the MTU at startup time and print some big error message into the log.
I will have a look at that, probably at the former rather than the latter.
Thanks once again.
Keith