[Dibbler] Relay Configuration Problem

Jimmy Ott admin at onnet.ch
Tue May 3 16:03:14 CEST 2005

it's a bit difficult to explain
i have this defaults from the project manager, and can't change the
layout, because a big part is configuring cisco routers :) the seminar
is nearly complete, DHCPv6 is only an additional goody, so i can't
change the setup. but i'm thinking about a separate network layout for
DHCPv6 education. thanks for your input

now, i've choosen your first approach, to make a node as relay which is
communicating via unicast to the dhcp server.

if you look at the picture mentioned before, the relay and one client is
in the subnet fd00:0:0:1::
the server is in the third one, and has a static ipv6 address
fd00:0:0:3::a, like described on the picture.

the client now sends a dhcpv6 solicitation message, the relay receive
this, and try to relay to fd00:0:0:3::a, but nothing happens, i also
don't see a packet when i trace with ethereal besides the IPv6
Solicitation Packet from the Client. the client try in different
intervals, as specified, to get an ip via the relay....

on the top of the relay log i see something very strange:
32:30 Notice    Creating srv unicast (fe80::200:39ff:fe24:d1e1) socket
on the Local Area Connection/5 interface.
32:30 Notice    Creating clnt multicast (ff02::1:2) socket on the Local
Area Connection/5 interface.

does the relay try to reach the routeable multicast address
fd00:0:0:3::a via it's link-local address????

on the server, i'm using the cvs version.
attached are the configs and the logs.

thank you very much for your professional help!!
cheers jimmy

Tomasz Mrugalski wrote:
> On Tue, 3 May 2005 somebody known as Jimmy Ott wrote:
>> we need this implementation to show on a seminar how IPv6 works, and
>> also how DHCPv6 with the Relay functionality works. So your second email
>> doesn't bring me further.
> I understand. In that case I suggest you to show some simple
> configuration: client-relay-server or client-relay1-relay2-server, with
> relays/routers set up on some linux boxes.
>> we are using hardware cisco routers, so the relay functionality does not
>> run on them.
> Too bad. I know that cisco provides limited DHCPv6 support. I'm not sure,
> but if I recall correctly, prefix delegation is the only supported option.
> So you say your routers are hardware ones. Hmmm, that limits some options.
> To provide most elegant solution (which is also best from the
> educational point of view), you could replace R1, R2 and R3 with one
> Linux box with 3 interfaces, radvd (to broadcast router advertisements)
> and dibbler-relay installed. Or 3 linux boxes if those links are
> physically distant.
> As for configuring relays with one interface... it kinda spoils the
> whole relay idea. And is definetly not recommended as a learning
> example. I consider this as a hack, a workaround, not a standard usage.
> Your students can get wrong impression that relaying is about modifying
> packet's addresses. I belive that relays were designed to work on
> routers. You will also have a problem describing interface-id idea as in
> this scenario both source and destination interfaces will be the same.
> If you require any more assistance, let me know.

-------------- next part --------------
# This is a configuration file for Dibbler client.

# Uncomment this to use short logging mode
log-mode short

# Client should request addresses and options on that interface
iface "Local Area Connection"

# request IA with just an address.
# request DNS configuration
    option dns-server
# request domain configuration
    option domain

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log-level 8
log-mode short

iface "Local Area Connection" {
  server multicast no
  server unicast FD00:0:0:3::a
  client multicast yes
  interface-id 1234
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log-level 7
log-mode short

iface eth0 {
 T1 1000
 T2 2000
 class {
   //pool fd00:0:0:1::-fd00:0:0:3::
   pool fd00:0:0:3::

 option dns-server fd00:0:0:3::a
 option domain ipv6class.net, ns1.ipv6class.net


iface relay1 {
  relay eth0
  interface-id 1234
  class {
    pool fd00:0:0:1::

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