[avahi] network down does not remove services
lennart at poettering.net
Wed Jan 13 11:41:23 PST 2010
On Wed, 13.01.10 12:16, ecfu (ecforusers at gmail.com) wrote:
> When a node on my network goes down, I notice my avahi-browse keeps the
> services from the gone node. Even if I kill the avahi-browse process and
> re-browse the services are still there. The only way to know that those
> services are gone is to try to resolve them (or at least that is all I have
> found that I can do). Am I just not waiting long enough?
> Is there a way to know that the node has dropped off and the services have
> been removed? Does this have to do with my network more than Avahi? Or is
> there a timeout configuration setting I can set?
If a service becomes unavailable and no goodbye packet is sent for it
(for examnple, because the network went away before the mDNS daemon
that registered it could send out a msg), then the TTL of DNS RRs will
control how long the entry lingers in the other peer's caches.
To put it simply: in modern IP networks there is no way to notice if a
machine dropped off the network. And since for traffic reasons we
cannot continously ping the machine we hence can get notified about
that only after a certain delay. There is no way around it.
Lennart Poettering Red Hat, Inc.
lennart [at] poettering [dot] net
http://0pointer.net/lennart/ GnuPG 0x1A015CC4
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