[Dnsmasq-discuss] Make RA_INTERVAL configureable? Deprecate old prefixes?

[Albert ARIBAUD]

Hi,

Le 16/07/2013 10:38, Uwe Schindler a écrit :
> Hi,
>
> I really like the dnsmasq implementation as replacement to my
> previous installation with radvd, because it closely integrates with
> DHCP. It also sends instant RA when a client requests DHCP, so it
> does not have to wait until the RA is sent out automatically.
>
> But I found a problem, especially happening with mobile phones
> (Android, Galaxy S3 in my case). When those go into sleep mode, they
> no longer listen to router advertisements, so after waking up, their
> address was already deprecated by the network stack and they have to
> wait for a new RA coming in. Unfortunately this happens too seldom
> (RA_INTERVAL is 600, means 10 minutes). They don't send any DHCP
> requests anymore, because the IPv4 DHCP lease is still fine (I have a
> lease time of 24 hrs for IPv4 leases, but 20 minutes for IPv6
> lifetime - because those are not really static - see below).
>
> Would it be possible to make the RA_INTERVAL configureable so I can
> send RAs in a periodic manner like with radvd? I would like to send
> RAs every 3 or 10 seconds like I had with radvd configured. This is
> not possible without patching dnsmasq.

Regardless of the interest of making the RA period configurable, why 
doesn't the mobile phone send out a Router Solicitation when it wakes up 
from sleep mode?

> A second thing related to RAs: I am living in Germany, where the
> assigned prefix to local networks is not really static (for privacy
> reasons), so it changes quite often (every 24hrs, enforced by DHCP
> prefix delegation on the PPPoE interface). When the prefix changes,
> dnsmasq should send (like radvd is doing) a zero lease time RA for
> the old prefix. I found out that dnsmasq.conf can set "deprecated" as
> life-time in the dhcp-range, but that would make all RAs going out
> have a time of 0s. It would be good if dnsmasq would send "active"
> prefixes with the given non-zero lifetime, but once a prefix
> disappears from the network adaptor, send extra RAs do deprecate the
> old prefix (using the old prefix with time=0) for a number of times.
>
> Uwe

Amicalement,
-- 
Albert.