dhcpcd-discuss

Hi Penq

On 2015-12-20 11:01, Peng Shao wrote:
> By doing so I was able to obtain a working /56 from my ISP, however a
> tcpdump analysis showed that radvd is sending RA to multicast every
> second no matter how often I set it to. Launching radvd in debug mode
> showed that it would "re-load" itself every second, causing this
> issue.

Could you post some context for this please?
radvd should announce why it's re-loading.

> It sounds almost to me that somehow dhcpcd was constantly "refreshing"
> network interfaces, causing radvd to see "new" interfaces every
> second, therefore reload itself accordingly every second afterwards.

At most, dhcpcd would bring an interface UP and add/delete addresses 
and/or routes.
Now, depending on kernel version and headers, it will delete a route 
every address refresh.
I don't recall which kernel version it was added in, but if it supports 
IFA_F_NOPREFIXROUTE then this will reduce dhcpcd altering the kernel 
routing table as much.

dhcpcd will refresh the DHCPv6 lease for the shortest lease it acquired 
- if it's low this could be what you're seeing.
Each time it is refreshed, dhcpcd will always add a new address, which 
will overwrite the old one. This is done so that the addresses added get 
new expiry times.

> I have no idea if this is a bug of radvd, dhcpcd or perhaps it is my
> incorrect dhcpcd.conf file. Using wide-dhcpv6-client for ipv6,
> isc-dhcp-client for ipv6 works normally for me in terms of working
> dual stack, though I still prefer dhcpcd since it is a lot faster to
> start/terminate. I reported this issue to radvd as well  as reporting
> it here. Hopefully it could be resolved soon. Thanks.
>
> By the way, I am attaching my dhcpcd log if it helps anyway.

The log output is fine, but ideally we want to see dhcpcd and rtadvd 
syslog messages at the same time to see what dhcpcd action is causing 
rtadvd to refresh.

Roy