Subject: Re: [Bugme-new] [Bug 28282] New: forwarding turns autoconfiguration off

From: Andrew Morton <[email-masked]>
Date: Tue, 8 Feb 2011 13:34:08 -0800

(switched to email.  Please respond via emailed reply-to-all, not via the
bugzilla web interface).

On Sat, 5 Feb 2011 18:06:31 GMT
[email-masked] wrote:

> https://bugzilla.kernel.org/show_bug.cgi?id=28282
> 
>            Summary: forwarding turns autoconfiguration off
>            Product: Networking
>            Version: 2.5
>     Kernel Version: 2.6.35
>           Platform: All
>         OS/Version: Linux
>               Tree: Mainline
>             Status: NEW
>           Severity: normal
>           Priority: P1
>          Component: IPV6
>         AssignedTo: [email-masked]
>         ReportedBy: [email-masked]
>         Regression: No
> 
> 
> Hi,
> 
> Linux ethernet interfaces do not use autoconfiguration and do ignore router
> advertisings if the packet forwarding is turned on in the configuration (i.e. 
> /proc/sys/net/ipv6/conf/eth0/forwarding set to 1)
> 
> 
> This might be wrong.
> 
> IPv6 network devices can have multiple IPv6 addresses and server several
> purposes at the same time. A machine can have a statically assigned local IPv6
> address and act as a router (e.g. to a virtual machine or a VPN tunnel) and
> thus needs to turn forwarding on, while at the same time it needs to listen to
> router advertisements and autoconfigure, e.g. because a network is connected to
> the internet through a DSL router with dynamically assigned network adresses,
> either through direct IPv6 assignment or a 6to4 tunnel. 
> 
> So there are cases where you need to have autoconfiguration of an IP address
> and forwarding on the same interface at the same time. Therefore, it might be
> technically wrong to have this mutually exclusive. 
>