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Mon, 30 May 2016 00:50:33 +0000 (UTC) (envelope-from kob6558@gmail.com) Received: by mail-ig0-x229.google.com with SMTP id ct2so22742450igb.0 for <net@freebsd.org>; Sun, 29 May 2016 17:50:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:sender:in-reply-to:references:date:message-id:subject :from:to:cc; bh=McjFoUGKPb6USpD0E7ZxGfY5+cwPId9MduNtjaH+ZWk=; b=sKa4Od5DwH3V2YGUSWmBZ70l2RisS4rVwwd2De6flbXuxSznSyrCDZlT1tJPIVuBFx IF07vjYfAI/Yd4r7bDIXetvq6zgquh8/rslD8S8CTBlSuBtqDJq6NXjGPbIBzMMxNttA ZL3Z4vluQ7ZOJBw3MGVETlcQlNNiRS1H1ArNG7bci9Ei0uQbFYXoMptJBpMderOR5tXt ju35UBikVhuLujlueGjphE82aUy5MT2V/JzlnEJB4YdNx/YjTNEtauWIk8vtPvKsZGj6 w4p/t+tBOYNkgPI7OsWBB+yXpHvigJ4/0ugIutFiuvv3se9/nLMq1yiON8wnwy9fdJlt 27BQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:sender:in-reply-to:references:date :message-id:subject:from:to:cc; bh=McjFoUGKPb6USpD0E7ZxGfY5+cwPId9MduNtjaH+ZWk=; b=G5YfsMn9xw4YBqXpDn05Amh+t+Q09Xus1PE3H5zq5SXuYZVo1tpOsVWCXO4nUAhrDC BIbMrMUXEpbMrRZrjqG8YafOe4MKycZy1d5ceg383j1WnJLXMQAHub6+Nw/KewRPr3rd Wy/3kd1Wmfhq3J3xFE+leAXqZuDnp7Y/bTkODnDMQ9excivMH5o8rhKVIWbeU3OFsk+V g/ngNQV/Ik/SundD8Jz8kCp7+88ALfkPPLRnN7w24sGseZG8AQD958IGQuLjUw40xxhI yOND/9PBCNfQkvssHNZtvCvRKTLZ+s35LYkKkAzIF1U9Fk29la30MUNqz1VDi0mjPsbI HXaQ== X-Gm-Message-State: ALyK8tLinkdbNN5C0xQ3zOfcDrlcorW14w70dpyjGNJhJuiQoZXEeIgetsr6cMr8MfBB+cIqs2EK8BvO9wN74g== MIME-Version: 1.0 X-Received: by 10.50.131.201 with SMTP id oo9mr6217856igb.15.1464569433171; Sun, 29 May 2016 17:50:33 -0700 (PDT) Sender: kob6558@gmail.com Received: by 10.79.20.70 with HTTP; Sun, 29 May 2016 17:50:33 -0700 (PDT) In-Reply-To: <20160529163228.I1958@besplex.bde.org> References: <20160528154122.C1843@besplex.bde.org> <SN1PR08MB1821D18DE13FB882ED3BA327BA430@SN1PR08MB1821.namprd08.prod.outlook.com> <20160529111806.I1012@besplex.bde.org> <20160529163228.I1958@besplex.bde.org> Date: Sun, 29 May 2016 17:50:33 -0700 X-Google-Sender-Auth: FSIxf4P2UAywrxfWysv_bAVswOg Message-ID: <CAN6yY1v8DdcHUt6aRBaMs1gsTY2d5296Zr0b8L=sqPoHSdq9Lw@mail.gmail.com> Subject: Re: ifconfig creates a bogus(?) route From: Kevin Oberman <rkoberman@gmail.com> To: Bruce Evans <brde@optusnet.com.au> Cc: David DeSimone <ddesimone@verio.net>, "net@freebsd.org" <net@freebsd.org> Content-Type: text/plain; charset=UTF-8 X-Content-Filtered-By: Mailman/MimeDel 2.1.22 X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.22 Precedence: list List-Id: Networking and TCP/IP with FreeBSD <freebsd-net.freebsd.org> List-Unsubscribe: <https://lists.freebsd.org/mailman/options/freebsd-net>, <mailto:freebsd-net-request@freebsd.org?subject=unsubscribe> List-Archive: <http://lists.freebsd.org/pipermail/freebsd-net/> List-Post: <mailto:freebsd-net@freebsd.org> List-Help: <mailto:freebsd-net-request@freebsd.org?subject=help> List-Subscribe: <https://lists.freebsd.org/mailman/listinfo/freebsd-net>, <mailto:freebsd-net-request@freebsd.org?subject=subscribe> X-List-Received-Date: Mon, 30 May 2016 00:50:34 -0000 On Sun, May 29, 2016 at 12:12 AM, Bruce Evans <brde@optusnet.com.au> wrote: > On Sun, 29 May 2016, Bruce Evans wrote: > > ... >> I still haven't figured out how to set up the bogus(?) route using route >> add/change, but can now complete the initialization using a "route change" >> that appears to be null: >> >> Test script: >> ... >> X # Fix up the initialization with a null change: >> X route change -iface 192.168.2.8 192.168.2.8 >> X netstat -rn >> > > Before: > >> ... >> Y Destination Gateway Flags Refs Use Netif >> Expire >> Y 127.0.0.1 link#2 UH 0 0 lo0 >> Y 192.168.2.0/24 link#1 U 0 0 em0 >> Y 192.168.2.8 link#1 UHS 0 0 lo0 >> Y route to: 192.168.2.8 >> Y destination: 192.168.2.8 >> Y interface: lo0 >> Y flags: <UP,HOST,DONE,STATIC> >> ... >> > > After: > >> ... >> Y Destination Gateway Flags Refs Use Netif >> Expire >> Y 127.0.0.1 link#2 UH 0 0 lo0 >> Y 192.168.2.0/24 link#1 U 0 0 em0 >> Y 192.168.2.8 192.168.2.8 UHS 0 0 lo0 >> Y route to: 192.168.2.8 >> Y destination: 192.168.2.8 >> Y interface: lo0 >> Y flags: <UP,HOST,DONE,STATIC> >> ... >> Note that the "null" route change just echos the current setting and it >> doesn't change anything according to netstat -rn and route -n, but it >> fixes up some internal state so that the ping works. When ping works, >> tcpdump shows it going from 127.0.0.1 to 192.168.2.8 and coming back as >> expected. When ping hangs, tcpdump shows it going from 0.0.0.0 to >> 192.168.2.8 and never coming back. The default route doesn't exist in >> either case. >> > > Bah, it did change (from link#1 to 192.168.2.8 for Gateway in netstat -rn > output only). -iface makes no difference (I thought it prevented this > change). > > The initialization bug has something to do with the magic default route > of 0.0.0.0). When lo0 is used uninitialized, it is still initialized > to 0 and the 0 gets copied to somewhere not shown properly in the > initial route from (or is it to?) 192.168.2.8. netstat -rn translates > this 0 together with another address to #link1, but route -n get > doesn't show it. I think this configuration is supposed to not occur. > I couldn't find a way to get back it using route(8) after fixing it. > > When lo0 is brought up first, different magic obscures what is > happening. E.g., when lo0 is misconfigured with "inet 127.0.0.127", > the em0 route is auto-configured with this strange lo0 address instead > of completely misconfigured to 0. Neither netstat -rn nor route -n > get displays this clearly (they give the same display as in the > uninitialized case except for the .127 route). Then if lo0 is > ifconfig'ed again to fix this misconfiguration, the all routes related > to the old lo0 (bogus or working) are deleted and not restored. But > if lo0 is brought up for the first time after em0, the the 0.0.0.0 > route related to the old lo0 is not deleted; it keeps breaking things. > > > Bruce > Bruce, When it is in the "broken" condition, what is the output of "route -n get 0"? So you have a default route? None appears in any of your messages. Normally 0 should route to default. In fact 0/0 is a definition of default. (Well, I suppose anything/0 is default, but 0/0 is the normal representation.) Since most systems have a default gateway defined, this may relate to the issue you are seeing. I'm very unclear what happens with 0/0 if default is not defined. FWIW, here is what I see on this system (10.3-STABLE r299096): Routing tables Internet: Destination Gateway Flags Netif Expire default 192.168.1.1 UGS re0 127.0.0.1 link#2 UH lo0 192.168.1.0/24 link#1 U re0 192.168.1.16 link#1 UHS lo0 -- Kevin Oberman, Part time kid herder and retired Network Engineer E-mail: rkoberman@gmail.com PGP Fingerprint: D03FB98AFA78E3B78C1694B318AB39EF1B055683