From owner-freebsd-net@FreeBSD.ORG  Mon Feb  9 16:37:49 2015
Return-Path: <owner-freebsd-net@FreeBSD.ORG>
Delivered-To: freebsd-net@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115])
 (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits))
 (No client certificate requested)
 by hub.freebsd.org (Postfix) with ESMTPS id 05A75B58
 for <freebsd-net@freebsd.org>; Mon,  9 Feb 2015 16:37:49 +0000 (UTC)
Received: from a0i241.smtpcorp.com (a0i241.smtpcorp.com [216.22.15.73])
 (using TLSv1.2 with cipher DHE-RSA-AES128-SHA (128/128 bits))
 (Client did not present a certificate)
 by mx1.freebsd.org (Postfix) with ESMTPS id D640BA85
 for <freebsd-net@freebsd.org>; Mon,  9 Feb 2015 16:37:48 +0000 (UTC)
DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=smtpcorp.com;
 s=a0_1; 
 h=Feedback-ID:X-Smtpcorp-Track:Message-ID:Date:Subject:To:From;
 bh=2uY1JXDe/hLUYh2F5Pd/ly/5ihwoNlpdQ6DZFQPpiHA=; 
 b=kc+ZHVmWxzb4cjXb4U/dL/hVXa0liMkjRmM37BRHmnLHZ/5C8UDJIk6WQSkwG6xs4Lw+CUOveDwTsOEE+g5WFSdyL4/olCZfWNnGI7wDw52hmEvF0BveJJufLW9gHZ5lI3sRZ+5H3Cr/11Ij/Ns7IrmwHRjDAMEYYXJ1WUHJGzQ=;
From: Daniel Corbe <corbe@corbe.net>
To: freebsd-net@freebsd.org
Subject: ifconfig greX create disables IPv6 forwarding
Date: Mon, 09 Feb 2015 11:34:02 -0500
Message-ID: <87h9uvjb7p.fsf@corbe.net>
User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.4 (gnu/linux)
MIME-Version: 1.0
Content-Type: text/plain
X-Smtpcorp-Track: 1YKrHfmkf1sC8j.2OF6pL6gn
Feedback-ID: 10661m:10661aegzayD:10661spkeXnS2L1:SMTPCORP
X-BeenThere: freebsd-net@freebsd.org
X-Mailman-Version: 2.1.18-1
Precedence: list
List-Id: Networking and TCP/IP with FreeBSD <freebsd-net.freebsd.org>
List-Unsubscribe: <http://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: <http://lists.freebsd.org/mailman/listinfo/freebsd-net>,
 <mailto:freebsd-net-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Mon, 09 Feb 2015 16:37:49 -0000


For some reason, every time I create a GRE interface on a FreeBSD IPv6
gateway, net.inet6.ip6.forwarding is disabled.  As long as I manually
re-enable it with sysctl, both the GRE tunnel and the IPv6 network
behind this machine will continue to work; however, it's certainly far
from ideal.

There's nothing in the log to indicate exactly what's going on here:

Feb  9 11:23:08 router rtadvd[27251]: interface added (idx=8)
Feb  9 11:23:08 router devd: Executing '/etc/pccard_ether gre0 start'
Feb  9 11:23:21 router rtadvd[27251]: non-zero lifetime RA but net.inet6.ip6.forwarding=0.  Ignored.
Feb  9 11:23:53 router last message repeated 2 times

Nor is there anything about it in dmesg.

# uname -a
FreeBSD router.corbe.net 10.1-RELEASE FreeBSD 10.1-RELEASE #0 r274401: Tue Nov 11 21:02:49 UTC 2014     root@releng1.nyi.freebsd.org:/usr/obj/usr/src/sys/GENERIC  amd64

-DAniel