[WireGuard] NAT-T Keepalives

[Jason A. Donenfeld]

On Thu, Jul 7, 2016 at 6:33 PM, Jason A. Donenfeld <Jason at zx2c4.com> wrote:
> 1. What should the payload be? Should it be a single fixed byte? Or
> should it be a zero length UDP packet?

Zero length.

> 2. What is an acceptable minimum interval? Every 5 seconds?

Every 10 seconds, so that we can only push the timer back on sending,
and then rely on the opportunistic keepalive for making things
coherent.

> 3. What is an acceptable maximum interval? 3600 seconds?

3600 seconds.

> 4. What is a good interval to show in documentation examples that will
> work for most people?

25 seconds, based on a massive survey of different routing equipment
in the wild.

> After this feature is ironed out, I'll be pushing a new experimental
> snapshot. This is currently the most visible headache of WireGuard and
> I'd like to get it ironed out sooner rather than later.

Ongoing work lives in this branch, which I'll merge soon:
https://git.zx2c4.com/WireGuard/log/?h=persistent-keepalive