implementing dhcpv6

sthaug at sthaug at
Wed Nov 4 19:43:08 UTC 2009

> Is RA an automatic function of IPv6 routers, or is it something the 
> administrator configures ? If it's something the admin needs to 
> configure, then I see little advantage (in a DHCP environment) over 
> using DHCP to configure the client, if it's automatic then how does 
> it know what the admin actually wants ?

As far as I know Cisco routers will automatically start sending RAs
on an interface as soon as you have configured an IPv6 address. If
you don't want that behavior you can explicitly turn the RAs off.

Juniper (M/MX/T) are the opposite - you need to explicitly configure
RAs if you want them sent. Which default is better is a matter of
personal preference (I prefer the Juniper default).

In any case, there is currently *no* standardized way to assign an
IPv6 default gateway to a host via DHCPv6.

For some of the religious discussion around this subject (rather
depressing to read at times), see for instance the thread starting

Steinar Haug, Nethelp consulting, sthaug at

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