[radvd-devel-l] radvdump not seeing RAs

Warren Steffen wsteffen at comcast.net
Sun May 20 13:28:56 EDT 2012

Reuben Hawkins wrote:
> On Fri, May 18, 2012 at 11:45 AM, Warren Steffen <wsteffen at comcast.net> wrote:
>> I am connected to Comcast ISP through a Motorola SB6120 cable modem. TCPDUMP
>> shows that are RAs on on the ethernet port of the modem. However radvdump
>> does
>> not show them. Am I missing something or doing something wrong?
>> W. Steffen
> Hi W.Steffen,
> I'm not sure.  I suggest trying to figure out exactly what it is
> you're seeing in TCPDUMP, or debugging radvdump.
> Do you get an autoconfigured IPv6 address?  If you're not, and you're
> not seeing anything on radvdump, I would think that TCPDUMP is showing
> incorrect info.
> You *may* be seeing IPv6 solicitations, not advertisements, in
> TCPDUMP, but that's just a guess.
> Thanks,
> Reuben
I am quite confidant of what I am seeing from tcpdump. I also have done
more testing and feel  it is NOT  an  radvd  problem . I now think it is
related to how the sysctl.conf file is processed. I have the following two
lines in that file:
If I have eth0 of my "router" system disconnected or connected to my
SB6120 modem, i do not have: /proc/sys/net/conf/eth0/accept_ra = 2
I do not have even: /proc/sys/net/conf/eth0
If I have eth0 of the same "router" system connected to a test system,
that has radvd etc running, the entries in /proc... are correct and the
router will accept the RAs, and also configure the interface (eventually
10-15 sec). My problem now is to find out why!
Thank you VERY much for your reply.

W. Steffen

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