Hi,

I found out that most so-called "bozos that query every second" where in 
fact proxies that give access to the internet to several machines through 1 IP.

Obviously, the proxy admin should set up its own ntp servers, but here is 
a tip for proxy configuration (MASQUERADE types) for well aware 
proxy admins (I don't remember seeing it elsewhere):

TIP : catch all outgoing connections to ports 123, 37 and 13 and redirect 
them to your own ntp servers. This way, it doesn't matter how the machines 
you are fronting are configured, they all end up querying your own ntp 
servers. So zero reconfiguration of your client machines is needed, 
clients do not need to be reconfigured with your own ntp servers IPs

In linux it looks like this, it depends on your network set-up :

This could be extended to any outgoing router even if doesn't masquerade 
the packets.

NTP-IP=your ntp server IP
EXTIF3=your network interface to your client machines

for redirport in 123 37 13
do
$IPTABLES -A FORWARD -i $EXTIF3 -p tcp --dport $redirport -m state \
--state NEW,ESTABLISHED,RELATED -j ACCEPT
$IPTABLES -A PREROUTING -t nat -p tcp -s ! $NTP-IP -d 0.0.0.0/0 
--dport $redirport \
-j DNAT --to $NTP-IP:$redirport

$IPTABLES -A FORWARD -i $EXTIF3 -p udp --dport $redirport -m state \
--state NEW,ESTABLISHED,RELATED -j ACCEPT
$IPTABLES -A PREROUTING -t nat -p udp -s ! $NTP-IP -d 0.0.0.0/0
--dport $redirport \
-j DNAT --to $NTP-IP:$redirport

done


Louis Goulet
[EMAIL PROTECTED]
cell: (418) 564-3527
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