On Sat, 28 Jan 2006 16:03:55 +0000, Tony Hoyle <[EMAIL PROTECTED]>
wrote:

>I'm seeing a number of 'abusive' clients, although it's not too bad 
>(only 3 at at <5 second intervals so at the moment) - I was wondering 
>about automating a script to firewall the offenders.
>
>However, since UDP is a connectionless protocol it seems to me it 
>wouldn't achieve a lot (since server load isn't an issue on that box). 
>The packet has already taken up bandwidth to get to me..   All I'd be 
>saving is the reply packet - is it worth it?  What have others done?
>
>Tony

Filtering at my _firewall_ (not by ntpq -c monlist) and
triggering at >450 queries an hour saves me 30% of my 
outbound traffic - which is useful as I am on ASDL.

Fri Jan 27 06:25:01 GMT 2006
 955K   73M ntp-filter-in  udp dpt:123
 595K   46M ntp-filter-out udp spt:123
Sat Jan 28 06:25:02 GMT 2006
 869K   66M ntp-filter-in  udp dpt:123
 560K   43M ntp-filter-out udp spt:123

Worst abuser so far in my logs (1 off - not seen since) -
Tue Nov  1 04:54:29 2005 - 61.229.xxx.xxx averaged 67650 pkt/hr (sent
451 pkts in 24 seconds).

On average I block about 15-20 addresses.

best regards
Dave
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