IPv6 Deployment for the LAN

Sun Oct 18 08:03:12 UTC 2009

On 18 Oct 2009, at 01:55, Ray Soucy wrote:
> The only solution that lets us expand our roll out IPv6 to the edge  
> without major changes to the production IPv4 network seems to point  
> to making use of DHCPv6, so the effort has been focused there.
[...]
> Needless to say, the thought of being able to enable IPv6 on a per- 
> host basis is met with far less resistance than opening up the  
> floodgates and letting SLAAC take control.

Hi, Roy --

Good summary, thanks for the write-up.

I reluctantly just use SLAAC on our own office LANs because, we're  
still quite a small and nimble team, therefore we can secure our  
network against our SLAAC security concerns by locking down access to  
the network.  I realise this isn't going to work for everyone, as it  
doesn't fit well for the security needs of your much larger campus  
network.  It also doesn't work for some of our customers who have DHCP  
in their toolbox for provision certain hosting environments.

DHCPv6 today lacks default-router option support, so you are left with  
some pretty awful choices if you don't want to use the router  
solicitation/advertisement, err, 'features' in SLAAC :

  - Static route on the device
    - Actually, you could use the *same* link-local address to keep  
this the same on all devices on your network, which you continue to  
support long after a "better" protocol comes along.  This reduces your  
support overhead.

  - end user runs some routing protocol
    - I don't want to give my router the extra work though.  And it  
feels like a stupid idea.  And end user OSes don't tend to have them  
installed.

  - Don't roll v6 beyond engineering teams, until something better  
comes along
    - Sadly, I think that this is the option people are taking. :-(

I don't know the history of the process that led to DHCPv6 ending up  
crippled, and I have to admit that it's not clear how I signal this  
and to whom, but for the avoidance of doubt: this operator would like  
his tools back please.  Support default-routing options for DHCPv6 !

Andy

-- 
Regards, Andy Davidson    +44 (0)20 7993 1700    www.netsumo.com
NetSumo Specialist ISP/networks consultancy, Whitelabel 24/7 NOC