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 E27DCC433EF for ; Mon, 21 Feb 2022 21:44:48 +0000 (UTC) Received: by lists.zx2c4.com (OpenSMTPD) with ESMTP id f08806c3; Mon, 21 Feb 2022 21:44:46 +0000 (UTC) Received: from rin.romanrm.net (rin.romanrm.net [2001:bc8:2dd2:1000::1]) by lists.zx2c4.com (OpenSMTPD) with ESMTPS id 2cdc176a (TLSv1.3:AEAD-AES256-GCM-SHA384:256:NO) for ; Mon, 21 Feb 2022 21:44:45 +0000 (UTC) Received: from nvm (nvm2.home.romanrm.net [IPv6:fd39::4a:3cff:fe57:d6b5]) by rin.romanrm.net (Postfix) with SMTP id 4BC1F6A9; Mon, 21 Feb 2022 21:44:44 +0000 (UTC) Date: Tue, 22 Feb 2022 02:44:43 +0500 From: Roman Mamedov To: Michael Tokarev Cc: wireguard@lists.zx2c4.com Subject: Re: WireGuard Windows should have default MTU of 1280. Message-ID: <20220222024443.1efe2c02@nvm> In-Reply-To: <20220222005710.705a7023@nvm> References: <6ba013e9-05db-17bc-995b-11ef1f279c91@msgid.tls.msk.ru> <20220222005710.705a7023@nvm> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit 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" On Tue, 22 Feb 2022 00:57:10 +0500 Roman Mamedov wrote: > On Mon, 21 Feb 2022 22:16:22 +0300 > Michael Tokarev wrote: > > > 21.02.2022 22:11, Michael Adams wrote: > > > Throwing in my two cents: I was using MTU 1280 on Tinc a few years back, for IPv6 VPN support on Windows & Linux. It's good practice. > > > > Lemme guess. The OP is routing wg packets over IPv6? Can this be > > the problem here, because V6 has larger overhead so that 1420 is > > too large to fit into 1500 bytes together with IPv6 header? > > 1420 is picked specifically so that it fits into a 1500 byte packet with IPv6. > > If you run WG exclusively over IPv4, you can use up to 1432. Correction: 1440. https://www.mail-archive.com/wireguard@lists.zx2c4.com/msg01856.html I'm just used to subtracting 8 everywhere, because my ISP *does* use PPPoE. :) -- With respect, Roman