Linux IPv6 routing strange behaviour

Hannes Frederic Sowa hannes at
Wed Aug 14 21:00:06 CEST 2013

On Wed, Aug 14, 2013 at 09:30:01PM +0300, Max Tulyev wrote:
> OMFG 8-|
> What is the soultion? There are *MILLIONS* of flows in the backbone...

Discard them fast enough. ;)

The garbage collector is called if you reach the limit (in the code
path). But sometimes it cannot free enough entries. In that moment
you should see a warning message in dmesg which should point you to
route/max_size. If that is not the case, I guess you could also have another

Also read up on the other knobs in /proc/sys/net/ipv6/route/*gc*. You should
handle a fairly decent throughput but as soon as a lot of udp/dns packets
traverse the router it might get a bit critical. But that is the case with
every flow based routing architecture.



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