On 9/16/10 4:53 PM, Mr Dash Four wrote:
> 
>>>> 4)  In the interfaces file:
>>>>
>>>>    If 'blacklist' is specified with no ZONE, a warning is given
>>>>    and the option is ignored.
>>>>
>>>>    If 'blacklist' is specified with a ZONE, it is equivalent to
>>>>    specifying 'blacklist' in the IN_OPTIONS column of the
>>>>    corresponding entry in the zones file.
>>>>
>>>>    Currently, incoming blacklisting is performed as a first step
>>>>    on incoming packets on those interfaces having the 'blacklist'
>>>>    option. With the new approach, blacklisting would occur after
>>>>    the packet has been processed against the interface-related
>>>>    options such as 'nosmurfs', 'tcpflags', etc.
>>>>   
>>>>       
>>> Is there any reason for this? For me it would not make sense to do ANY 
>>> processing (ddos etc) if this packet is/has failed the blacklist test.
>>>     
>>
>> It's a consequence of the order in which the ruleset is constructed.
>> Interface-oriented filtering is generated well before zone-oriented
>> filtering. During optimization, interface-oriented filtering can be
>> moved to the front of a zone-oriented chain. It's something that could
>> be overcome but it's not trivial.
>>   
> Bugger! I can see a potential for some really nasty stuff coming from 
> this. Is there absolutely no chance that the blacklist processing could 
> be moved forward, somehow?

I don't think that the consequences could be that dire (a blacklisted
host could renew its DHCP lease is the only hole I can see), but it is
not horribly difficult to remove this restriction.

-Tom
-- 
Tom Eastep        \ When I die, I want to go like my Grandfather who
Shoreline,         \ died peacefully in his sleep. Not screaming like
Washington, USA     \ all of the passengers in his car
http://shorewall.net \________________________________________________

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