v6 & DSL / Cable modems

Mikael Abrahamsson swmike at swm.pp.se
Sat Feb 7 15:59:16 UTC 2009

On Sat, 7 Feb 2009, sthaug at nethelp.no wrote:

> This does not seem to be generally true:
> - For the routers I am most familiar with (Juniper M/MX), you need to
> explicitly turn on router advertisement to make the router perform this.
> I.e. it is perfectly possible to have an interface with an IPv6 address
> which does *not* send RAs.

Cisco routers do send RA by default as soon as IPv6 is enabled on the 

> - For the operating system I am most familiar with (FreeBSD), RAs are
> *not* accepted by default if the interface in question is configured
> with a static IPv6 address.

Linux (at least Debian/Ubuntu kernels) will accept RAs by default even if 
you set a static IPv6 address. To stop it you have to do:

sysctl net.ipv6.conf.eth0.accept_ra=0

Mikael Abrahamsson    email: swmike at swm.pp.se

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