tinc - May 2017 - Multiple default gateway from tinc node

Hi, Tinc expert

If there’re multiple tinc nodes announce default route in their host
configuration of Subnet = 0.0.0.0/0, how for the remaining nodes to select which
is the best route to get out?

All of them participant in the same tinc net.

I did some test, like A as the branch, B,C,D as the nodes to announce default
route; when all up , A select B, but if B down, A will go C, C down, A will go
D, but is there any rules?

Also, if the connection is in a hierarchy, and enabled IndirectData = yes
everywhere, so the tunnel only follow the meta connection, if this is the case,
what’s the default routes selection rule?

Hello,


Am Mon, 1 May 2017 23:35:53 +0800
schrieb Bright Zhao <startryst at gmail.com>:
> If there’re multiple tinc nodes announce default route in their host
> configuration of Subnet = 0.0.0.0/0, how for the remaining nodes to select
> which is the best route to get out?
it is important to understand that tinc only takes care for exchanging metadata
(e.g. "subnet" definitions of available hosts).
Thus it is up to you (and probably your "subnet-up" script) to turn
these
information into a routing setup.
Probably the following subnet-up script is suitable for many use-cases:

  #!/bin/sh
  ip route add "$SUBNET" dev "$INTERFACE" metric
"$WEIGHT" 2>/dev/null || true

Please note the "$WEIGHT" variable (see "man tinc.conf") -
it will take care for
the "priority" of the default gateways.

Cheers,
Lars

Hi, Lars

Thanks for your suggestion, will give it a try later to see how it performs.

But, yesterday, I did a below test:

A ConnectTo B and C, B ConnectTo D, C ConnectTo D; All nodes turned
"IndirectData" on in its host configuration, so the tunnel only follow
metacomnection instead of direct connect.

D announced default route by having the Subnet = 0.0.0.0/0 statement in its host
config

The tunnel next hop for A set to C(for Mac, to config the tunnel interface, you
have to specify the next hop)

And I point A's default route next hop to C as well.

In this case, A's traffic route to Internet is go through C to D to
internet, but If I add Subnet =0.0.0.0/0 on B, the traffic seems go directly
from A to B to internet.

Since A have both ConnectTo to B and C(To D through C), and the default gateway
set to C, why A chose B instead of D's default route?

At this moment, if I shutdown B's tinc daemon, the traffic path for A to
Internet return back to: to C and the to D

During the whole process, A's default gateway point to C.

Sent from iPhone
> 在 2017年5月2日，上午4:37，Lars Kruse <lists at sumpfralle.de> 写道：
> 
> Hello,
> 
> 
> Am Mon, 1 May 2017 23:35:53 +0800
> schrieb Bright Zhao <startryst at gmail.com>:
> 
>> If there’re multiple tinc nodes announce default route in their host
>> configuration of Subnet = 0.0.0.0/0, how for the remaining nodes to
select
>> which is the best route to get out?
> 
> it is important to understand that tinc only takes care for exchanging
metadata
> (e.g. "subnet" definitions of available hosts).
> Thus it is up to you (and probably your "subnet-up" script) to
turn these
> information into a routing setup.
> Probably the following subnet-up script is suitable for many use-cases:
> 
> #!/bin/sh
> ip route add "$SUBNET" dev "$INTERFACE" metric
"$WEIGHT" 2>/dev/null || true
> 
> Please note the "$WEIGHT" variable (see "man
tinc.conf") - it will take care for
> the "priority" of the default gateways.
> 
> Cheers,
> Lars
> _______________________________________________
> tinc mailing list
> tinc at tinc-vpn.org
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