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 045F2C7113B for ; Wed, 23 Aug 2023 23:31:49 +0000 (UTC) Received: by lists.zx2c4.com (ZX2C4 Mail Server) with ESMTP id 59f2b257; Wed, 23 Aug 2023 23:31:48 +0000 (UTC) Received: from mail-il1-x162.google.com (mail-il1-x162.google.com [2607:f8b0:4864:20::162]) by lists.zx2c4.com (ZX2C4 Mail Server) with ESMTPS id 47c319fe (TLSv1.3:TLS_AES_256_GCM_SHA384:256:NO) for ; Wed, 23 Aug 2023 20:47:41 +0000 (UTC) Received: by mail-il1-x162.google.com with SMTP id e9e14a558f8ab-34b4b2608e3so19396705ab.3 for ; Wed, 23 Aug 2023 13:47:40 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1692823660; x=1693428460; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:dkim-signature :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=EeUMBL8J2+MKiX6cdx35XzWLRbrmjHX99nubGCiUCek=; b=UaJJbAuGFp30BAuGALrc3LxEjMSalWSSPNIrM5S3AW4hdwzUJGhkjIUjMqaoASXET1 o+tmYf+YR47QogMkYkMntH2eomIDxXCcRwLJ0r+crf+Rf5RAgrRS3CwQGiC+xlrQRAaM 9Sg9J1wkGqB3CevASnX7hJmFbfBz7ikDRrqtfByJ+4x01yuu6Wzt4Wu7dOc5nH8i33J8 qRHAWNA7F1RW5dCYb2/D8sV1Afg5n3HoyZKAV9okCybGc88enwLDBSH87A2CZvhI1eHz L/odHcZZNY6WK4aE43Y7GOy3DJfHJnxtw+9i40AFtWjA/M6zR5OMhiZc8OQfOec+N66n sgKQ== X-Gm-Message-State: AOJu0Yz/1CywTRLETMEEOYS3ng1fUPqOfxBnm/nIoqur+2UWVbnHZQ2O 65T0BTaKd0V9APVSjSuRBKInhsxE4z++liHfl6yscQiQX+8tqUOv7/aZnFn8 X-Google-Smtp-Source: AGHT+IFw9AngzB0bXLnIu1AFdQgMUbVBU22Glj4pZ0R/xFexBe4sSBhKmTvT6o7d/Oxfe18/iOSqgzBdyALl X-Received: by 2002:a92:cd86:0:b0:33a:a6de:65be with SMTP id r6-20020a92cd86000000b0033aa6de65bemr4184697ilb.21.1692823659699; Wed, 23 Aug 2023 13:47:39 -0700 (PDT) Received: from restore.menlosecurity.com ([13.56.32.44]) by smtp-relay.gmail.com with ESMTPS id x18-20020a92de12000000b0034992fd508csm621754ilm.38.2023.08.23.13.47.39 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 23 Aug 2023 13:47:39 -0700 (PDT) X-Relaying-Domain: menlosecurity.com Received: from safemail-prod-02900067cr-re.menlosecurity.com (13.56.32.45) by restore.menlosecurity.com (13.56.32.44) with SMTP id 4b1a5040-41f6-11ee-b71d-1b6a3dac80bd; Wed, 23 Aug 2023 20:47:39 GMT Received: from mail-pj1-f70.google.com (209.85.216.70) by safemail-prod-02900067cr-re.menlosecurity.com (13.56.32.45) with SMTP id 4b1a5040-41f6-11ee-b71d-1b6a3dac80bd; Wed, 23 Aug 2023 20:47:39 GMT Received: by mail-pj1-f70.google.com with SMTP id 98e67ed59e1d1-26d50941f68so6989041a91.1 for ; Wed, 23 Aug 2023 13:47:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=menlosecurity.com; s=google; t=1692823657; x=1693428457; 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=EeUMBL8J2+MKiX6cdx35XzWLRbrmjHX99nubGCiUCek=; b=JGLOKF8/ku7+6Cf5YTYXznilZcQumfSSkh7ev5oJ96LxlpR/GudRjnkKVZuV8T/Se8 ZM7+KHoYtyAbfASjufz8eYtRqKcDK6qoEeAxERiHBF+n7vrqtPe4Pb8/i8Ssc3fS4PjJ frH0nyJSxxQd/+0qNnq5zAGZ/s7Pkh4mlHibo= X-Received: by 2002:a17:90a:f3d5:b0:263:f630:228f with SMTP id ha21-20020a17090af3d500b00263f630228fmr13004221pjb.23.1692823656731; Wed, 23 Aug 2023 13:47:36 -0700 (PDT) X-Received: by 2002:a17:90a:f3d5:b0:263:f630:228f with SMTP id ha21-20020a17090af3d500b00263f630228fmr13004207pjb.23.1692823656420; Wed, 23 Aug 2023 13:47:36 -0700 (PDT) MIME-Version: 1.0 References: <20230823165840.7bf3b910@parrot> <20230823171451.ld2fwslkl6blv6y2@House.clients.dxld.at> In-Reply-To: From: Hugo Slabbert Date: Wed, 23 Aug 2023 13:47:25 -0700 Message-ID: Subject: Re: IPv6 and PPPoE with MSSFIX To: Luiz Angelo Daros de Luca Cc: =?UTF-8?Q?Daniel_Gr=C3=B6ber?= , =?UTF-8?B?TWFyZWsgS8O8dGhl?= , wireguard@lists.zx2c4.com Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Mailman-Approved-At: Wed, 23 Aug 2023 23:31:43 +0000 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" > 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. For ref, an L2TP + PPPoE stack isn't too uncommon, and gives you 20 bytes overhead from the 12 bytes L2TP + 8 bytes PPPoE. On Wed, Aug 23, 2023 at 12:02=E2=80=AFPM Luiz Angelo Daros de Luca wrote: > > > 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 actu= ally > > correct. MTU=3D1440 is only correct on top of IPv4, for IPv6 the "optim= al" > > 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