From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-x232.google.com (mail-wi0-x232.google.com [IPv6:2a00:1450:400c:c05::232]) (using TLSv1 with cipher RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by huchra.bufferbloat.net (Postfix) with ESMTPS id 4AA4E201904 for ; Thu, 29 May 2014 16:36:35 -0700 (PDT) Received: by mail-wi0-f178.google.com with SMTP id cc10so181273wib.17 for ; Thu, 29 May 2014 16:36:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type:content-transfer-encoding; bh=FEHfoGPINepxvv0e/4eVJX1ThsjL4mKKuGwyTQ/PzBw=; b=dbN9EvGnib00/cgaQONFUdMhHVpjCzooxLdf8MVuRtomqSklULEq0WS6dtsKQUkHbq uny8g8wXoiXRYv+IfVW5N7LWZ2fCz4nIFIseNm7JDPf2gwFHs/tKRwAasPfojQ3uxMXF DZb5/XsktIzmF9F6QAYEgU2rcNXjkg6W/mkpxO9mK4haQyvcqF5wceW6BTQkvz26+rAi BGsvKmjYPXRIevAQTSVu7EEpxlkgF/e5vCw/9qNEmGFiQbFWe64zk/RlegXodI5uFit1 rTuctkxvHJqXrBWzs0HFp5VDD7EhWMQPOnUMcMYPAp+FjhDNUkp3Crdk87JYiQeAoJSU WW8w== MIME-Version: 1.0 X-Received: by 10.194.6.106 with SMTP id z10mr15245120wjz.1.1401406593340; Thu, 29 May 2014 16:36:33 -0700 (PDT) Received: by 10.216.207.82 with HTTP; Thu, 29 May 2014 16:36:33 -0700 (PDT) In-Reply-To: References: Date: Thu, 29 May 2014 16:36:33 -0700 Message-ID: From: Dave Taht To: "cerowrt-devel@lists.bufferbloat.net" Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Subject: Re: [Cerowrt-devel] possible ipv6 path mtu issue, address assignment, and dhcpv6 renews X-BeenThere: cerowrt-devel@lists.bufferbloat.net X-Mailman-Version: 2.1.13 Precedence: list List-Id: Development issues regarding the cerowrt test router project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 29 May 2014 23:36:35 -0000 On Thu, May 29, 2014 at 1:54 PM, Dave Taht wrote: > I've had a couple reports of "slowness" on native ipv6, and possibly > there is some sort of path mtu issue being forced, by something. > > What I am seeing is ipv4 "bytes on the wire" is 1514, but > native ipv6 "bytes on the wire" is 1494, according to wireshark. > > Any attempt to send a "native" 1514 size tcp packet gets an ETOOBIG > icmp response. (In an age of short tcp transactions this is bad) > > The topology is host - cero1 - cero2 - internet > > There is a he tunnel (mtu 1480) and comcast on the link I'm testing, > and the ETOOBIG is coming from the internal interface of cero2. I will > disable the tunnel there... but arguably, using source specific > routing, it should only be stuff being forwarded through the tunnel > that would give that error... and this happens before it gets to the > tunnel. I disabled the tunnel and now 1514 byte ipv6 packets do get through. It's rather unclear why the lower tunnel mtu was causing problems though... > > The second thing I'm seeing periodically, for no reason I can tell, is th= at > I'm getting an address on a network that doesn't exist on that host. > > d@nuc:~$ ifconfig eth0 > eth0 Link encap:Ethernet HWaddr ec:a8:6b:fe:09:a2 > inet addr:172.26.4.20 Bcast:172.26.4.31 Mask:255.255.255.224 > inet6 addr: fe80::eea8:6bff:fefe:9a2/64 Scope:Link > inet6 addr: 2601:9:6680:4aa::3ce/64 Scope:Global > exists > inet6 addr: 2601:9:6680:56a::3ce/64 Scope:Global > doesn't exist > > Could be some other device on the link supplying it, but doesn't seem so. > I will keep monitoring radvdump... It looks like dhclient6 on the host gets wedged somehow and this isn't a cerowrt problem. I filed a bug on it here. http://www.bufferbloat.net/issues/443 If your underlying ipv6 address changes and you get stuck with an old one, or an old one keeps coming back, well... > > The third, is like others here, I'm not seeing dhcpv6 renews work. by this, I meant, not seeing them in the web interface. Another problem is I'm not getting a default route from ras for some reason= . Sigh. > -- > Dave T=C3=A4ht > > NSFW: https://w2.eff.org/Censorship/Internet_censorship_bills/russell_029= 6_indecent.article --=20 Dave T=C3=A4ht NSFW: https://w2.eff.org/Censorship/Internet_censorship_bills/russell_0296_= indecent.article