Why use DHCPv6 over Stateless Address Autoconfiguration

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IPv6 and RFC 2462 provide a means for hosts to configure their own IP addresses via stateless address autoconfiguration. To me this seems like the bee's knees, and it leaves me wondering why someone would want to go through the trouble of configuring a DHCPv6 server instead. I don't manage networks as a profession, so I'm guessing that there are some obvious simple reasons why one would want to support DHCPv6 that don't occur to me. Could someone please elaborate on what these reasons might be?

Best Answer

DHCPv6 provides more control to the administrator in assigning addresses. If you really want that sort of control over your IPv6 addresses, you don't understand IPv6 yet.

It also can be used to provide additional configuration parameters beyond the basic address/gateway supported through autoconfiguration. An example might be WINS servers, NTP servers, TFTP boot servers, and other less common options. None of which are worth the pain of deploying a DHCPv6 architecture in my opinion.

Stick with autoconfig.

Related Solutions

Centos – IPv6 stateless autoconfiguration not working on CentOS 6.2

Here is the relavent bits from the kernel documentation about forwarding. And Router Solicitations/Advertisements.

forwarding - BOOLEAN
        Configure interface-specific Host/Router behaviour.

        Note: It is recommended to have the same setting on all
        interfaces; mixed router/host scenarios are rather uncommon.

        FALSE:

        By default, Host behaviour is assumed.  This means:

        1. IsRouter flag is not set in Neighbour Advertisements.
        2. Router Solicitations are being sent when necessary.
        3. If accept_ra is TRUE (default), accept Router
           Advertisements (and do autoconfiguration).
        4. If accept_redirects is TRUE (default), accept Redirects.

        TRUE:

        **If local forwarding is enabled, Router behaviour is assumed.**
        This means exactly the reverse from the above:

        1. IsRouter flag is set in Neighbour Advertisements.
        2. **Router Solicitations are not sent.**
        3. **Router Advertisements are ignored.**

Windows – Use Windows DHCP/DHCPv6 server without setting a static address

Now I know I said setting up a ULA was not an option but it is actually far easier than I thought. You do not need to publish the prefix. And no other address in the ULA subnet even needs to exist anywhere.

Yes, it is a garbage address that clutters up the routing table but at least it doesn't get into other machines.

Hopefully Microsoft will take note at some point and allows their DHCPv6 server to respond on other available addresses besides static. It makes sense to require a static address during stateful address assignment in order to reliably map scopes to interfaces. But it does not apply to stateless DHCPv6.

Unfortunately, there is no other answer to this question.

Best Answer

Related Solutions

Centos – IPv6 stateless autoconfiguration not working on CentOS 6.2

Windows – Use Windows DHCP/DHCPv6 server without setting a static address

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