Multiple default gateway from tinc node

[Guus Sliepen]

On Tue, May 02, 2017 at 09:16:53AM +0800, Bright Zhao wrote:

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

It might look that way, but it doesn't. I assume you did something like
this on A:

ip route add default via <C's VPN IP address> dev $INTERFACE

However, the "via <some address>" part is only something that has any
effect on Ethernet networks. If tinc is in router mode, your VPN is a
pure layer 3 network. There are no Ethernet headers, only IP headers. IP
headers only have a source and destination IP address, they don't
contain any information about a gateway. So when tinc gets a packet, it
can only route based on the final destination.

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