From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.zx2c4.com (lists.zx2c4.com [165.227.139.114]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 0FB97C3DA66 for ; Wed, 23 Aug 2023 19:02:09 +0000 (UTC) Received: by lists.zx2c4.com (ZX2C4 Mail Server) with ESMTP id 29bd1fea; Wed, 23 Aug 2023 19:02:08 +0000 (UTC) Received: from mail-lj1-x22e.google.com (mail-lj1-x22e.google.com [2a00:1450:4864:20::22e]) by lists.zx2c4.com (ZX2C4 Mail Server) with ESMTPS id b3ccccd8 (TLSv1.3:TLS_AES_256_GCM_SHA384:256:NO) for ; Wed, 23 Aug 2023 19:02:06 +0000 (UTC) Received: by mail-lj1-x22e.google.com with SMTP id 38308e7fff4ca-2bcc331f942so1928871fa.0 for ; Wed, 23 Aug 2023 12:02:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1692817325; x=1693422125; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=6AqwDDeg4x5Kaq/Cjpy0zQfYDndzy1lfMtgpx208iY8=; b=aLnfWTyJh8mgKQZ5UzYdDEAprrXv4XdiMAtki+0rs4+sZhDhdYKmtwV001crsRGmbn n++GXiehysrzxDGfQ6/C4boGxw1VhL7wCtRYMVR0tMjwThmv2ENBMUEAPMF60bEz8A2x dv6i2aqQedWC5Oxq159M8E7cVU3ETXsGT7cZCzQgGamNLI2cmSgdFLA1CbOanF2BbFMP JX8Da1gb+ebmcdcl5JPewVeHvI9h8MpaRM8FLcu/LcQfi/APbYZOM1viveb+z1LiM0Bu pWYblZsxnbikciQC5Im9T//Dw8qgvc2NF3OLguS0oD/p+yGo1/CSObrFTZDjsh+VHMBp Agtg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1692817325; x=1693422125; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=6AqwDDeg4x5Kaq/Cjpy0zQfYDndzy1lfMtgpx208iY8=; b=kOHvBJVN3QnDYLKJmdsvYXCPycST9Y/A3RJVs8gERLlLkF4w/PJuZTrDW9qzGvcg0/ jpBMshHyz7UCVJSxdS//6QF7DfYazodepnONH5BOBx5L3iWanDeAvthb0z/A/clS2OWV 6Cd4vZMAy9R8KeDjVqtfUdQ/FCR4rL+8hzC0/KII8XtTZL3PzP1nW5N+ViPuOy4wK2hY Q+E1IhOWXF4zCCrpZIKbITdjP03Dqy4R8WqYqxrSvjnbseldWobaN48ABujaowb5msaO Ua+uWz/hSL+JJE2Vp/pqlBDLEj1ex2b6feiQv/iKrm4vIzlcBj956PZlexH06k32s27c yNUw== X-Gm-Message-State: AOJu0YzvWkDQwT0wmaw5a6wse+V5ZJRdvUAFyap+nuulHPo9cMn/rman pADojnlKLVSdOQjb+kJx/zjThU7DZzVzY8w1iYikTSHUD05fDw== X-Google-Smtp-Source: AGHT+IEpNmvAytiP3h+3WCZlCyWMuB7qL0KzbBiMkz4RtyuvZ25sM2xNTSzbKcSP/AN3V8v4onNv7cusaSAlgU30Bu4= X-Received: by 2002:a2e:9dd3:0:b0:2bc:bae4:a933 with SMTP id x19-20020a2e9dd3000000b002bcbae4a933mr3900254ljj.17.1692817325122; Wed, 23 Aug 2023 12:02:05 -0700 (PDT) MIME-Version: 1.0 References: <20230823165840.7bf3b910@parrot> <20230823171451.ld2fwslkl6blv6y2@House.clients.dxld.at> In-Reply-To: <20230823171451.ld2fwslkl6blv6y2@House.clients.dxld.at> From: Luiz Angelo Daros de Luca Date: Wed, 23 Aug 2023 16:01:53 -0300 Message-ID: Subject: Re: IPv6 and PPPoE with MSSFIX To: =?UTF-8?Q?Daniel_Gr=C3=B6ber?= Cc: =?UTF-8?B?TWFyZWsgS8O8dGhl?= , wireguard@lists.zx2c4.com Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-BeenThere: wireguard@lists.zx2c4.com X-Mailman-Version: 2.1.30rc1 Precedence: list List-Id: Development discussion of WireGuard List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: wireguard-bounces@lists.zx2c4.com Sender: "WireGuard" > Hi, Hi Daniel, > On Wed, Aug 23, 2023 at 04:58:40PM +0200, Marek K=C3=BCthe wrote: > > PPPoE adds 8 bytes of overhead so that an MTU of 1432 can be used. I > > also have to do this at home with my DSL line for example. > > The MTU should be set on each side (on both peers) for this to work. > > Oh, I just realized I used the 1432 MTU in my earlier reply based on > Marek's math but since Luiz's underlay network is IPv6 this is not actual= ly > correct. MTU=3D1440 is only correct on top of IPv4, for IPv6 the "optimal= " > MTU is 1420 so with PPPoE involved that's MTU=3D1412. > > 1500 Ethernet payload > -40 IPv6 header > -8 UDP header > -32 Wg header > -8 PPPoE > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D > 1412 wg tunnel MTU In my case, the PPPoE interface got MTU=3D1480. They might be stacking something else on top of it or PPPoE might have optional fields. I read somewhere that PPPoE might use either 8 or 20 bytes, but I'm not an expert on PPPoE. If I don't control both sides, I would use 1400 by default. > --Daniel