[Dibbler] Hand out default route information

Tomasz Mrugalski thomson at klub.com.pl
Tue Jun 6 09:02:04 CEST 2006

On Mon, 5 Jun 2006 somebody known as Wiegand, Steven wrote:

> I would like to have a host receive a default route along with an
> address from the dibbler DHCPv6 server. I realize that DHCPv6 should not
> configure routing, but here is my problem.
That is not possible. As been states many times before, DHCPv6 is not 
designed for configuring routing.

> In my current configuration I have a Dibber DHCPv6 server, a Dibbler
> DHCPv6 Windows 2003 client, and a relay router (Cisco) between them.
> I'd like my host to only get the DHCPv6 assigned address and not an
> autoconfigured address from the router's RA.  If I enable the DHCPv6
RA can contain multiple entries about different routes. For each (among 
other flags), there are two:
AdvOnLink - if this prefix is available on this link
AdvAutonomous - if hosts are allowed to generate IPv6 addresses in this 
prefix all by themself

Of course, second flag can only be set if the first one is set.
As I'm definetely Linux guy, I can't help you much with Windows or Cisco 
routers. But This might be interesting for you. Here is my /etc/radvd.conf 
configuration file. If you want to make this work, get some Linux box with 
radvd installed (this software is included in all major distros), copy 
this file to /etc/radvd.conf and run the radvd service.

---- cut here ----
interface eth1 {
         AdvHomeAgentFlag on;
         AdvHomeAgentInfo on;
         AdvSendAdvert on;
         MinRtrAdvInterval 600;
         MaxRtrAdvInterval 1200;
         AdvDefaultLifetime 7200;
# announce this prefix, as available locally, but hosts should not
# generate addresses by themselves
         prefix 3ffe:8320:3:210::1:1/64 {
                 AdvOnLink on;
                 AdvAutonomous off;
                 AdvRouterAddr on;
# announce this prefix as available locallby and hosts should
# generate their SAA address automatically
         prefix 3000::/64 {
                 AdvOnLink on;
                 AdvAutonomous on;
                 AdvRouterAddr on;
---- cut here ---

> I looked into disabling the address parameter of the RA process, but I
> didn't come across anything.
I'm sure that this is possible. After some googling I've found this:

(see "ipv6 nd prefix-advertisement" description)

Here is full command syntax:
ipv6 nd prefix-advertisement ipv6-prefix/prefix-length valid-lifetime 
preferred-lifetime [onlink] [autoconfig]
Try this:
ipv6 nd prefix-advertisement 3000::/64 3600 1800 onlink

Just don't use autoconfig flag. I don't have any Cisco router to verify 
this, but this should do the thick.

Hope that helps.

Tomasz Mrugalski,              | "I think there is a world market for     |
thomson(at)klub(dot)com(dot)pl |  about five computers."                  |
                                |     Thomas J. Watson (Chairman, IBM) 1943|

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