Routing

Hello all - I recently came into a new position and am looking at the DHCPv6 configuration.  I prefer my configs to be as concise as possible to ease management and troubleshooting, and am trying to wrap my head around this one.  I wanted to see if anyone had any thoughts.

Core router is an MX960.  All DHCP and DDNS functions are handled by an Infoblox appliance, for both v4 and v6.  Everything is functioning normally at the current time - this is mainly for future reference as we add more v6 networks.

1 - All v6-enabled interfaces are configured for router advertisements, with the correct prefix and the no-autonomous knob.  Since all DHCP functions are handled by the appliance, does the router need to send out RAs, or are the router-advertisement statements unneeded?

2 - We also have 'set protocols router-advertisement interface all managed-configuration', which does make perfect sense.  I assume that also sets the other-stateful-configuration bit, or should we explicitly include it with 'set protocols router-advertisement interface all other-stateful-configuration'?

Seems like such simple questions, and for DHCPv4 I feel very comfortable with the setup.  The v6 config hasn't clicked in my head yet.  I appreciate any feedback.  Thanks.

Louis

Louis, great questions and you are on a good track. Let me add some tidbits to clarify and also answer your questions.

According to standards, IPv6 clients should only request for addr and/or info from a DHCPv6 when told to do so, by an RA. Also, clients get their IPv6 def g/w -only- from an RA (not via DHCPv6, this is different than in DHCP) via the L flag being on (generally its default). There is a bit of descrepncy on L required to be on or off and do the clients need it. I have seen mixed results in all my testing...best rule of thumb, leave L on for clients.

So on questions:

1) you need RAs for all subnets/vlans that have clients/devices. You don't need them for p2p links. And you are good for turning the A flag off for Stateful operations. But you must have M flag on for Stateful (DHCPv6) operations. More info next.

2) if the M flag is on, that implies that the clients request is for an IPv6 address as well as for "other info" like dns/domain name, d/l servers, etc. If you set the O flag on while M is on, there is nothing gained, or hurt (my preference: M on, O doesn't matter, but I leave O off. Basically, O flag is used with A flag for Stateless DHCPv6 (A flag on for client to get prefix and self-derive IID, O flag on for DHCPv6 for dns/domain, etc).

You have done well!

hth...Jeff

Jeff, Thank you so much for the response, this was exactly what I was looking for.  I have to give credit to my team as well, who had most of this set up already.  But I'm very glad to know we're going down the right path.  Cheers!

Louis