Option UDPOnly missing?

[Guus Sliepen]

On Mon, Mar 20, 2017 at 02:32:16PM +0100, borg at uu3.net wrote:

> I noticed that there is no UDPOnly option. Why so?
> I prefer to control traffic as much as possible..
> 
> I belive, currently, when there is loss of connectivity,
> tinc tries TCP too to restore connectivity... If succeed,
> it needs to switch back to UDP then... Right?
> 
> So, can tinc use only UDP? Or it needs TCP for some metadata
> communication?

Tinc needs TCP for its metadata communication. This requires reliable,
in-order transmission, which is exactly what TCP provides.

Tinc indeed switches to TCP for VPN traffic if UDP is not possible. It
should however switch back to UDP once that becomes available again. If
you don't want it to use TCP for VPN traffic, then you can set
PMTUDiscovery = no. This disables the probes tinc uses to detect if UDP
is possible. However, the probes also help with NAT traversal, so if you
are behind a NAT then this might completely break communication between
two peers.

-- 
Met vriendelijke groet / with kind regards,
     Guus Sliepen <guus at tinc-vpn.org>
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