Limit DHCP requests with iptables - problem: Router
Simon Hobson
dhcp1 at thehobsons.co.uk
Wed Aug 29 22:09:19 UTC 2012
Dorsey, Chris wrote:
>We are seeing a lot of induced IO wait due to processing/logging of
>unwanted DHCP requests from *known* MAC addresses (broken printers,
>mis-behaving clients, etc.) and were very interested in this thread.
...
> or enhancing dhcpd with the ability to allow for
>administrator-configured filtering.
You can do things like add a host statement with an "ignore booting"
directive. This should be fairly cheap in processing terms and
shouldn't clutter the logs.
Also, consider why you are getting IO performance issues. For
logging, make you you configure the logging as async. The default on
many setups is sync logging which means a sync (and potentially
multiple disk writes/seeks) for each log message which will quickly
consume IO resources.
--
Simon Hobson
Visit http://www.magpiesnestpublishing.co.uk/ for books by acclaimed
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