Development discussion of WireGuard
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From: Ashish SHUKLA <ashish.is@lostca.se>
To: Roman Mamedov <rm@romanrm.net>
Cc: wireguard@lists.zx2c4.com
Subject: Re: Force a specific IP for outgoing WG traffic with SNAT?
Date: Sat, 18 Mar 2023 01:13:53 +0530	[thread overview]
Message-ID: <e4f7dc477cd14e14a75e304878e6cb05@lostca.se> (raw)
In-Reply-To: <20230217000747.0825b2e9@nvm>

On 2023-02-17 00:37, Roman Mamedov wrote:
> Hello,
> 
> I'm trying to move all my WG communication with peers to a non-primary
> IP of my server.
> 
> It has IPs added like this:
> 
>     inet6 2001:db8::ca6c/128 scope global deprecated
>        valid_lft forever preferred_lft 0sec
>     inet6 2001:db8::1/128 scope global nodad
>        valid_lft forever preferred_lft forever
> 
> What I tried:
> 
>   ip6tables -t nat -I POSTROUTING -d 2000::/3 -p udp --dport 51820 -j
> SNAT --to-source 2001:db8::ca6c
> 
> Also tried to filter by --sport, and also briefly without a port filter 
> at all.
> 
> This has zero effect, as shown by tcpdump all the WG traffic still
> originates from 2001:db8::1
> 
> Does anyone have an idea why is that? Thanks

Did you try filtering based on fwmark ?

     CONFIGURATION FILE FORMAT
            The configuration file format is based on INI. There are two 
top level sections -- Interface and Peer. Multiple Peer sections may be 
specified, but only one Interface section may be specified.

            The Interface section may contain the following fields:

            •      PrivateKey — a base64 private key generated by wg 
genkey. Required.

            •      ListenPort — a 16-bit port for listening. Optional; if 
not specified, chosen randomly.

            •      FwMark — a 32-bit fwmark for outgoing packets. If set 
to 0 or "off", this option is disabled. May be specified in hexadecimal 
by prepending "0x". Optional.

HTH
-- 
Ashish

"It could be that the purpose of your life is only to serve as a warning 
to others." (Ashleigh Brilliant)

  reply	other threads:[~2023-03-17 19:44 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-02-16 19:07 Roman Mamedov
2023-03-17 19:43 ` Ashish SHUKLA [this message]
2023-03-17 19:54   ` Roman Mamedov

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