ssh + IPV6 + bridge => connection freezes

[Steve O'Hara-Smith]

On Sun, 24 Apr 2011 11:04:30 -0700 (PDT)
Matthew Dillon <dillon at apollo.backplane.com> wrote:

> 
> :	Hi,
> :
> :	If IPV6 is enabled on a box and a bridge interface is enabled on
> :the same interface then any ssh connection to the box using the IPv6
> :address will freeze after a little activity (30 seconds of typing random
> :commands seems to be enough), bringing the bridge down with ifconfig will
> :restore activity to the ssh sessions (left alone they time out). I have
> seen :this with both 32 and 64 bit systems using up to date master code.
> :
> :	I'm also not sure that it's appropriate for a bridge interface to
> :have an IPv6 link local address - perhaps this is connected.
> :
> :-- 
> :Steve O'Hara-Smith                          |   Directable Mirror Arrays
> 
>     This is probably an issue with the MAC learning for the bridge.
>     IPV6 works differently than IPV4, I think the MAC is built into
>     the IPV6 address and there's no interface ARP (not sure though).

	IPv6 has autogenerated addresses (both link local which is always
there - the fe80 ones and global ones issued by something running rtadvd or
similar - but only if rtsold is running) with the MAC embedded in the
address, but you can also use explicitly issued addresses with no relation
to the MAC, which I do for anything I actually want to be able to reach
reliably.

	IPv6 uses NDp (Neighbor Discovery Protocol) which looks pretty
complex (five kinds of ICMP involved).

-- 
Steve O'Hara-Smith                          |   Directable Mirror Arrays
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