m0n0 comes with dnsmasq (http://www.thekelleys.org.uk/dnsmasq/doc.html). 
Add
echo "127.0.0.1        ads.youdontlikeit.com" >> /etc/hosts
for every site You don't like at boot time somehow and tell dnsmasq to 
reload /etc/hosts if needed (not sure).

Pat Ellison wrote:
> This would be incrediblly usefull.. Block al those *&^($ doubleclick sites..
> 
> 
> 
> -----Original Message-----
> From: Craig [mailto:news at craigio dot co dot uk]
> Sent: Sunday, August 01, 2004 7:29 AM
> To: m0n0wall at lists dot m0n0 dot ch
> Subject: Blocking Web addresses
> 
> 
> Hello, I am looking for a solution to control the ability of blocking
> websites, or shall I say block all and allow certain authorised websites.  I
> like the compactness of M0N0Wall,  and I am wondering if there is a way of
> doing this with this system.  Any ideas?
> 
> Craig
> 
> 
> 
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