From: Nico Schottelius <nico.schottelius@ungleich.ch>
To: Roman Mamedov <rm@romanrm.net>
Cc: Nico Schottelius <nico.schottelius@ungleich.ch>,
tlhackque <tlhackque@yahoo.com>,
wireguard@lists.zx2c4.com
Subject: Re: Source IP incorrect on multi homed systems
Date: Sun, 19 Feb 2023 22:19:23 +0100 [thread overview]
Message-ID: <87h6vh72d4.fsf@ungleich.ch> (raw)
In-Reply-To: <20230220014252.21178988@nvm>
Hey Roman,
Roman Mamedov <rm@romanrm.net> writes:
> On Sun, 19 Feb 2023 21:18:34 +0100
> Nico Schottelius <nico.schottelius@ungleich.ch> wrote:
>
>> If I am not mistaken that would mean in practice:
>>
>> if orignal_pkg.ip_dst == one_of_my_ips then
>> return_pkg.ip.src = orignal_pkg.ip_dst
>> return_pkg.ip.dst = orignal_pkg.ip_src
>> fi
>>
>> For me that sounds like a sane approach (aside from
>> my very simplified algorithm).
>
> Except there is no request and response in WG, and as such no original or
> return packet. Another peer contacts you, then some time later you contact the
> other peer. Or the other way round.
>
> WG-wise what will need to be done is to store in the each peer's information
> structure the local IP that we are supposed to use for communication with that
> peer; and updating it when receiving packets from the peer, using the
> destination of those. So you would see a "Local IP" in each "peer" section
> when doing a "wg show".
That is very interesting, thanks for the insight. Reading above
paragraph, I was having a very similar thought that we need to record
the local IP.
> Also, until there is such IP initially stored, it will have to be some default
> outgoing IP of the system towards that peer. BTW, how would this work in your
> setup, what if not the peer contacts you first, but your machine needs to
> contact the peer?
So far this situation doesn't exist for us, because only servers are
multi homed.
However, having an option to specify something a local address in each peer
section would probably be a good solution to disambiguate it and if not
specified, use the default, as in whatever other processes are using
that don't define it explicitly - i.e. follow the process of least
surprise.
Best regards,
Nico
--
Sustainable and modern Infrastructures by ungleich.ch
next prev parent reply other threads:[~2023-02-19 21:50 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-18 20:14 Nico Schottelius
[not found] ` <CAHx9msc1cNV80YU7HRmQ9gsjSEiVZ=pb31aYqfP62hy8DeuGZA@mail.gmail.com>
2023-02-18 22:34 ` Nico Schottelius
2023-02-19 0:45 ` Mike O'Connor
2023-02-19 8:01 ` Nico Schottelius
2023-02-19 9:19 ` Mikma
2023-02-19 12:04 ` Nico Schottelius
2023-02-19 12:10 ` Nico Schottelius
2023-02-19 18:59 ` Peter Linder
[not found] ` <2ed829aaed9fec59ac2a9b32c4ce0a9005b8d8b850be81c81a226791855fe4eb@mu.id>
2023-02-19 12:13 ` Nico Schottelius
2023-02-19 14:39 ` Christoph Loesch
2023-02-19 16:32 ` David Kerr
2023-02-19 16:54 ` Sebastian Hyrvall
2023-02-19 18:04 ` Janne Johansson
2023-02-19 18:08 ` Sebastian Hyrvall
2023-02-19 20:11 ` Nico Schottelius
2023-02-19 17:05 ` tlhackque
2023-02-19 18:37 ` David Kerr
2023-02-19 18:52 ` tlhackque
2023-02-19 18:42 ` tlhackque
2023-02-19 20:18 ` Nico Schottelius
2023-02-19 20:42 ` Roman Mamedov
2023-02-19 21:19 ` Nico Schottelius [this message]
2023-02-19 22:06 ` tlhackque
2023-02-19 22:42 ` Src addr code review (Was: Source IP incorrect on multi homed systems) Daniel Gröber
2023-02-20 0:28 ` 曹煜
2023-02-20 10:40 ` Nico Schottelius
2023-02-20 11:21 ` 曹煜
2023-02-20 9:47 ` Nico Schottelius
2023-02-20 20:43 ` dxld
2023-02-19 21:39 ` Source IP incorrect on multi homed systems tlhackque
[not found] ` <CADGd2DoE6TCtCxxWL7JWyNW5+yy_Pe+9MNzHznbudMWLTXQreA@mail.gmail.com>
2023-02-19 18:30 ` Fwd: " John Lauro
2023-02-19 22:28 ` tlhackque
2023-02-20 0:58 ` Luiz Angelo Daros de Luca
2023-02-19 20:02 ` Nico Schottelius
2023-02-20 11:09 Janne Johansson
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