From owner-freebsd-net@freebsd.org Sun Jul 2 16:58:04 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 71936DA919F for ; Sun, 2 Jul 2017 16:58:04 +0000 (UTC) (envelope-from herbert@mailbox.org) Received: from mx1.mailbox.org (mx1.mailbox.org [80.241.60.212]) (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 22A0E707CE for ; Sun, 2 Jul 2017 16:58:03 +0000 (UTC) (envelope-from herbert@mailbox.org) Received: from smtp1.mailbox.org (smtp1.mailbox.org [80.241.60.240]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.mailbox.org (Postfix) with ESMTPS id 9FA4046B55; Sun, 2 Jul 2017 18:57:58 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=mailbox.org; h= content-transfer-encoding:content-type:content-type:mime-version :references:in-reply-to:subject:subject:from:from:message-id :date:date:received; s=mail20150812; t=1499014676; bh=j9issO70oR vB7pIPxMlf2mJCz9dxN3jtP4slXL/GSms=; b=Xa0F7r3TIj3igHLdBz9DrPjjkG 5+FCYWCA5inS7AUOyQLIqMBMo7DewWUfkksC80Zbp0N2/9cHyItgKLgPfVJakrhg Rzhpi5FzCR0AbkRpd10QC7KS+237pNds2q2HhP8YQJZU98i4p9J1Yo53m3zmRjI8 b6geQX2N+7hDGlcDr1ZSDuovnT25cBQiUHDAv8YF8TII4kwTA+42ZVdVMIuG0f6V JjlJXO2BetyAG2Za5gtatquMw8Vrd1HvUxjQhyhFNIZEs/2X2Rgn2l7FBgjXgH5s FntH5qroUGkRByyBdHG1RxknH7Bn0Qq5Sc+gKiHlyni+olb71+7vBav0PuCg== X-Virus-Scanned: amavisd-new at heinlein-support.de Received: from smtp1.mailbox.org ([80.241.60.240]) by hefe.heinlein-support.de (hefe.heinlein-support.de [91.198.250.172]) (amavisd-new, port 10030) with ESMTP id EKLN6uixRwMW; Sun, 2 Jul 2017 18:57:56 +0200 (CEST) Date: Sun, 02 Jul 2017 18:57:54 +0200 Message-ID: <878tk6ydwt.wl-herbert@mailbox.org> From: "Herbert J. Skuhra" To: Eugene Grosbein Cc: 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: <59590FE6.7030109@grosbein.net> References: <87r2xzaw30.wl-herbert@mailbox.org> <87bmp3x7eu.wl-herbert@mailbox.org> <59590064.1040700@grosbein.net> <87a84myitf.wl-herbert@mailbox.org> <59590FE6.7030109@grosbein.net> MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=KOI8-R Content-Transfer-Encoding: quoted-printable 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 16:58:04 -0000 Eugene Grosbein skrev: > = > 02.07.2017 22:11, Herbert J. Skuhra =D0=C9=DB=C5=D4: >> Eugene Grosbein skrev: >>> = >>> 02.07.2017 21:03, Herbert J. Skuhra wrote: >>>> Skype for Business (S4B) on Mac OS X 10.12.6 (Beta5) is actually >>>> trying to connect over IPv4. The connection fails until I lower MT= U to >>>> 1440. After resetting MTU to 1500 and restarting S4B it connects f= ine >>>> for a while ('route -n get' default shows 1500). I use 'set iface >>>> enable tcpmssfix' in mpd5.conf and I've tried: >>>> = >>>> - set iface mtu and set link mtu/mru/mrru in mpd5.conf >>>> - set scrub ... max-mss in pf.conf >>> = >>> Please show output of ifconfig command for external ng interface. >> = >> ng0: flags=3D88d1 me= tric 0 mtu 1440 >> inet6 fe80::XXX:XXXX:XXXX:XXXX%ng0 prefixlen 64 scopeid 0x7 = >> inet XX.XX.XX.XX --> XX.XX.XX.YY netmask 0xffffffff = >> nd6 options=3D21 > = > 'set iface enable tcpmssfix' in mpd.conf should be enough for you. > = > Are you sure you have it in right point of the config? > This is critical for it to take effect. Please see mpd.conf.sample fo= r example. > = > Doesn't mpd complain of this command to its log? No. > Make sure you have 'log +iface +iface2' command in your mpd.conf, > restart mpd5 and scan its log for 'tcpmssfix'. mpd: [B1] IFACE: Connecting tcpmssfix But when I disable IPv6 on my network everything is working... even without tcpmssfix enabled. Instead of enabling ipv6cp in mpd5 I've also tested with an IPv6 tunnel= from HE... same issue. :-( -- Herbert