What is wrong with the IPv6 RA protocol ? - FEHCom

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Figure 3: Multiple Router Advertisements on a link segment
In order to configure the IPv6 settings on a
Linux host, one may apply the following settings:
The standard ifconfig command.
The Linux-specific ip command.
The kernel configuration command sysctl.
The /proc file system, in particular
/proc/sys/net/ipv6/.
The Linux kernel imposes a silent concurrency
limit on the received RA information.
Only a limited number of Prefixes
are accepted. The RA option DNS Recursive
Resolvers however is ignored.
Neither the ifconfig nor the ip command
can be used to configure the processing of ND
or RA messages; rather this is subject of the
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sysctl kernel configurations. Linux accepts
by construction RA messages and acts upon
those accordingly.
Linux provides the following settings [lis. 1]:
net . ipv6 . c o n f . a l l . accept_ra_defrtr=1
net . ipv6 . c o n f . a l l . accept_ra_pinfo=1
net . ipv6 . c o n f . d e f a u l t . accept_ra_defrtr=1
net . ipv6 . c o n f . d e f a u l t . accept_ra_pinfo=1
net . ipv6 . c o n f . l o . accept_ra_defrtr=1
net . ipv6 . c o n f . l o . accept_ra_pinfo=1
net . ipv6 . c o n f . eth0 . accept_ra_defrtr=1
net . ipv6 . c o n f . eth0 . accept_ra_pinfo=1
net . ipv6 . c o n f . s i t 0 . accept_ra_defrtr=1
net . ipv6 . c o n f . s i t 0 . accept_ra_pinfo=1
Listing 1: Linux sysctl default settings
We realize that the RA options Prefix and
Routing can be fine-tuned specifically. It is
remarkable, that the ’all’ and ’default’ parameter
settings have no influence on a specific
interface. Further, it is doubtful to include