tinc - Jun 2017 - Reliability between TCPonly and UDP for tinc?

If the concern is more about the reliability instead of throughput, should I add
TCPonly = yes in the host configuration to make the VPN runs on TCP?

The only time I can think off, that you’ll *want* to use TCP, is when UDP
doesn’t work through the firewalls/NATting.
> On 18 Jun 2017, at 14:53 , Bright Zhao <startryst at gmail.com>
wrote:
> 
> If the concern is more about the reliability instead of throughput, should
I add TCPonly = yes in the host configuration to make the VPN runs on TCP?
The problem with TCP, is that TCP, encapsulated inside a TCP stream, is a recipe
for very poor performance, as you could have retransmits, encapsulated in
retransmits.

But then the questions might be more like: Have you read up about why VPNs over
TCP isn’t a good idea?
And since you have, what reliability issues are you having with tinc over UDP?
And if you have those reliability problems over UDP, what tests have you done to
confirm it’s not the network, but the UDP that is less reliable than the TCP VPN
settings?

I agree with the in-effective of TCP transmission, but I wonder if the the UDP
packet is dropped, the tinc VPN itself wouldn’t retransmit, and if the upper
level application doesn’t handle the packet loss well, will this be the problem?

Or the upper level application have very limited tolerance to packet loss(like
RDP application, I guess if the packet loss go to certain threshold, the
connection will be lost).
> On 18 Jun 2017, at 9:25 PM, hvjunk <hvjunk at gmail.com> wrote:
> 
> The only time I can think off, that you’ll *want* to use TCP, is when UDP
doesn’t work through the firewalls/NATting.
> 
>> On 18 Jun 2017, at 14:53 , Bright Zhao <startryst at gmail.com>
wrote:
>> 
>> If the concern is more about the reliability instead of throughput,
should I add TCPonly = yes in the host configuration to make the VPN runs on
TCP?
> 
> The problem with TCP, is that TCP, encapsulated inside a TCP stream, is a
recipe for very poor performance, as you could have retransmits, encapsulated in
retransmits.
> 
> But then the questions might be more like: Have you read up about why VPNs
over TCP isn’t a good idea?
> And since you have, what reliability issues are you having with tinc over
UDP?
> And if you have those reliability problems over UDP, what tests have you
done to confirm it’s not the network, but the UDP that is less reliable than the
TCP VPN settings?
> 
> 
> 
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