From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: bounce+1a9445.bb0-wireguard=lists.zx2c4.com@poorlab.com Received: from krantz.zx2c4.com (localhost [127.0.0.1]) by krantz.zx2c4.com (ZX2C4 Mail Server) with ESMTP id 50616a13 for ; Sun, 12 Aug 2018 19:44:56 +0000 (UTC) Received: from m32-4.eu.mailgun.net (m32-4.eu.mailgun.net [141.193.32.4]) by krantz.zx2c4.com (ZX2C4 Mail Server) with ESMTP id 7d9ea3b1 for ; Sun, 12 Aug 2018 19:44:56 +0000 (UTC) Sender: coder@poorlab.com Received: by mail-qk0-f182.google.com with SMTP id 191-v6so9651703qki.13 for ; Sun, 12 Aug 2018 12:56:34 -0700 (PDT) MIME-Version: 1.0 References: <20180813000611.3296fa66@natsu> In-Reply-To: <20180813000611.3296fa66@natsu> From: StarBrilliant Date: Mon, 13 Aug 2018 05:55:59 +1000 Message-ID: Subject: Re: Fragmentation on UDP layer possible? To: wireguard@lists.zx2c4.com Content-Type: text/plain; charset="UTF-8" List-Id: Development discussion of WireGuard List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Mon, Aug 13, 2018 at 5:06 AM Roman Mamedov wrote: > > On Mon, 13 Aug 2018 02:53:44 +1000 > StarBrilliant wrote: > > > I know Wireguard can already do IP layer fragmentation. (Just set > > tunnel MTU >= 1441 then fragmentation will be turned on) > > Is that really expected to work? I tried setting MTU 9000 on both ends of a WG > tunnel, but large packets still do not seem to come through properly. Did you > try using it like that in any kind of environment (aside from that one > restrictive network)? > > In theory using MTU 9000 or such would help lower the huge overhead percentage > of running IP over VXLAN over IP over WG over IP. I was looking into that the > other day, but my idea was to fragment VXLAN packets across multiple WG ones, > which turned out to be impossible (VXLAN RFC forbids fragmentation). I have succeeded in setting a MTU of 1966 bytes inside VXLAN with a non-restrictive Ethernet. Due to a Linux bug, you need to do "sudo ethtool -K vxlan0 rx off tx off", or all UDP packets will have wrong checksums and being dropped. You might want to check my project on generating a Wireguard+VXLAN with a tool https://github.com/m13253/VxWireguard-Generator (Note that this is not production-ready. In other words, please back up your main database often)