[support] Why should we disable /proc/sys/net/ipv6/conf/all/accept_ra ?

[Arnaud Ebalard]

Hi,

Russell Valice <russell.valice at gmail.com> writes:

> According to http://www.nautilus6.org/doc/nepl-howto/, I do as
>
> echo 0 > /proc/sys/net/ipv6/conf/all/accept_ra
>
> I don't know why we should disable? Any certain reasons?

UMIP performs router discovery on its own: it sends RS, parses received
RA containing Prefix Information Options and then configure CoA based on
that info. To avoid interferences from the kernel (parsing and address
config), UMIP set various /proc keys, among which 

   /proc/sys/net/ipv6/conf/XXX/accept_ra_defrtr
   /proc/sys/net/ipv6/conf/XXX/accept_ra_pinfo

where XXX is the iface being configured (set to value 0). This prevents
parsing of RA received *from default router* and handling of PIO. I
don't know precisely why /proc/sys/net/ipv6/conf/XXX/accept_ra is not
set to 0 but I see no obvious reason. The path is referenced in
src/proc_sys.h but not used in the code. May have been forgotten ...

BTW, It is funny you ask, because I was looking at that code (for SEND
support) during the week-end and wrote a patch to do just that by
default.

Cheers,

a+