[radvd-devel-l] radvd on dynamicly appearing/disappearing interfaces

[Pekka Savola]

On Sat, 21 Feb 2009, Arkadiusz Miskiewicz wrote:
>> On Wed, 4 Feb 2009, Arkadiusz Miskiewicz wrote:
>>> It seems that currently radvd doesn't notice that configured interface is
>>> gone and then up again. What are possibilities to improve this?
>>>
>>> (real life situation: radvd on openvpn managed interface; service openvpn
>>> restart and radvd no longer sends ra on the interface).
>>
>> Which radvd version are you running?  In radvd, there were changes to
>> this, and it should reactivate the interfaces when they're back.
>> Setting "IgnoreIfMissing on;" additionally quences some error
>> messages.  Prior to 1.0, IgnoreIfMissing might have brought you
>> what you were looking for.
>
> radvd 1.2
>
> This option helps since when radvd starts the openvpn interfaces are not yet
> available. Is there a reason why it is not on by default?

If radvd is started after openvpn is up, and you do restart openvpn, 
radvd should work even without this flag (it'll just take another RA 
interval cycle).  If it doesn't, there's a problem with automatic 
restarting.

Radvd ignoring missing interfaces at boot has been intentional, and I 
believe it's useful at least in some cases -- for example you mistype 
the interface in the configuration, and that interface is never going 
to show up, yet radvd keeps trying to use it (restarting itself) 
indefinitely.  That would be bad.

So, for this second problem, I think the right approach is to start 
radvd only after openvpn has been started (or use the flag).

But if there are others who feel this way, I could consider ignoring 
the missing interface at startup, yet logging error messages about 
that.

-- 
Pekka Savola                 "You each name yourselves king, yet the
Netcore Oy                    kingdom bleeds."
Systems. Networks. Security. -- George R.R. Martin: A Clash of Kings