From owner-freebsd-net@freebsd.org Sun Jul 2 11:59:27 2017 Return-Path: Delivered-To: freebsd-net@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id A8915DA3FAA for ; Sun, 2 Jul 2017 11:59:27 +0000 (UTC) (envelope-from herbert@mailbox.org) Received: from mx2.mailbox.org (mx2.mailbox.org [80.241.60.215]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "*.mailbox.org", Issuer "SwissSign Server Silver CA 2014 - G22" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 5B43F64B44 for ; Sun, 2 Jul 2017 11:59:26 +0000 (UTC) (envelope-from herbert@mailbox.org) Received: from smtp2.mailbox.org (smtp2.mailbox.org [80.241.60.241]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx2.mailbox.org (Postfix) with ESMTPS id 4AEC6467D4 for ; Sun, 2 Jul 2017 13:59:18 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=mailbox.org; h= content-type:content-type:mime-version:references:in-reply-to :subject:subject:from:from:message-id:date:date:received; s= mail20150812; t=1498996756; bh=qKEZpkzin1+0egYGskKp7FNBbzb1LYTps SH0+v1j1ak=; b=dgiJpSC0a8S/+0zX+DvO2YxKKprGUq7uU/8crD6M3fYOPhcSj /RkCGCMZUVBumldSaTBk2gBdV6w1KrOjPHVFy8j1cHAyphVxufENF89wV3VBKVcz AKlz7oqJY4jvyoofcfVyTGnTqvTBRWsNVYHQMTH0BNtqhQ9Zbch/BHPsr5Y3OJdB 90zz19YVx8rrwrCdw7N8wfnnLISxjjkVwUCb1L13WOhqfbukekgdS3NnIoFeHaD0 hYLGHxDdlmmatFLEAQ3e2DqIqEnBAXSR6md/htfUAZe7OMENd8tTT2a2neeH9vHx WnjK0xVOqi4DNxif+CyJiCuOpxS2W6fw0Zxww== X-Virus-Scanned: amavisd-new at heinlein-support.de Received: from smtp2.mailbox.org ([80.241.60.241]) by spamfilter02.heinlein-hosting.de (spamfilter02.heinlein-hosting.de [80.241.56.116]) (amavisd-new, port 10030) with ESMTP id AuG-HpwdVaxR for ; Sun, 2 Jul 2017 13:59:16 +0200 (CEST) Date: Sun, 02 Jul 2017 13:59:15 +0200 Message-ID: <87r2xzaw30.wl-herbert@mailbox.org> From: "Herbert J. Skuhra" To: freebsd-net@FreeBSD.org Subject: Re: [Bug 220351] Path MTU discovery works only after resetting an internal interface MTU (mpd5, ng_nat, ipfw) In-Reply-To: References: MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 02 Jul 2017 11:59:27 -0000 bugzilla-noreply skrev: > > https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=220351 > Eugene Grosbein changed: > > What |Removed |Added > ---------------------------------------------------------------------------- > Assignee|freebsd-net@FreeBSD.org |eugen@freebsd.org > Status|New |Open > CC| |eugen@freebsd.org > > --- Comment #2 from Eugene Grosbein --- > (In reply to Martin Birgmeier from comment #1) > > Lowering interface MTU of internal machine also lowers its default route 'mtu' > attribute, see output of the command 'route -n get default'. > > Raising interface MTU back does NOT restore 'mtu' attribute of the default > route, so the kernel still uses 1492 as maximum IP packet size for packets > going via this route. > > Correct solution for your problem is 'set iface enable tcpmssfix' command in > the mpd.conf, see /usr/local/etc/mpd5/mpd.conf.sample for example. This way you > can keep default MTU=1500 for internal hosts and have no MTU-related network > problems. > > Please test and report back. I think I have a similar problem, but with IPv6 and pf! :-( - Problem to load e.g. https://www.heise.de on the first try - Can not connect to Skype for Business over IPv6 (unfortunately I sometimes need it for job) Everything else is obviously working. Does anyone know how to fix this? Thanks. -- Herbert