Subject: Re: unregister_netdevice: waiting for tun6to4 to become free.

From: Andre Tomt <[email-masked]>
Date: Thu, 23 Sep 2004 09:13:26 +0200

(CC'ed to netdev)

<snip>

I can taste the bug now :-)

Me and Thomas Graf have been discussing this a bit off-list; so for 
those on netdev, this is my current setup:

server A sets up a sit tunnel to server B. server B has a sit tunnel to 
Provider. All communication between A, B and Provider is going over 
ethernet on the physical layer.

server B is the one getting stuck in "waiting for <device> to become 
free.." when ifdown'ing (ip tunnel del) the interface to Provider.

If I boot with net.ipv6.conf.default.forward = 1 in sysctl.conf - but 
then after the boot do echo 1 > /proc/sys/net/ipv6/conf/all/forward (to 
actually get it running)

we'll crash and burn when taking down the interface.

Only setting /proc/sys/net/ipv6/conf/all/forward = 1, but never touch 
default, it goes down cleanly.

I have the ipv6/conf/default/forwarding set in sysctl.conf on all the 
routers, and it seems zebra sets the ipv6/conf/all/forwarding later on.