On Fri, 2011-09-30 at 11:43 +0100, Mr Dash Four wrote:
> > Yes. Traditionally, blacklisting has been done ahead of interface filters 
> > such as tcpflags, surfs, etc.
> And this is absolutely right - nothing should come before blacklisting.
> 
> >  Given that all 'src' blacklists are the same currently, a jump to the 
> > 'blacklst' chain can simply be moved to the interface input and forward 
> > chains. That isn't possible when there are multiple such blacklist rulesets.
> >   
> Why not? To use my example, the first rule (and jump) in the fw2vpn 
> chain is to a separately-created chain called "blackout". Granted, this 
> chain is "shared" among all fw2XX chains, but I can't see why would that 
> be any different if that jump is to a separate chain called, say, 
> vpn_blackout? In my "start" file, for that chain I have done exactly 
> that and I have been running this configuration successfully for quite 
> some time.

I assume, then, that you have no interfaces that support multiple zones.
In that case, the jumps for checking tcpflags, smurfs, etc. are in the
interface input and forward chains; the jumps to the blacklst chain are
promoted from the zone-specific chains to the interface chains. Again,
that works now because there is only one blacklst chain.

> 
> >> 
> > All of that makes me think again of the rules file. My problem is that if 
> > these rules are placed in the rules file, they will come after tcpflags, 
> > surfs, etc.
> >   
> I take it the only reason that blacklist statements/rules may be placed 
> (in iptables) after tcpflags etc is because of the time shorewall 
> processes the "rules" file, right? If that is the case, then I'd leave 
> them in the blacklist file - nothing should come before blacklist 
> processing!
> 
> I agree though, this "new" format is emerging to be similar to the rules 
> file where the "ACTION" column would consists of either "BLACKLIST" or 
> "WHITELIST", though I am not sure how would you process the "NEW", 
> "ESTABLISHED" and "RELATED" sections if they were to contain 
> blacklist/whitelist statements (that is provided the blacklist 
> statements go into the "rules" file, which I am not sure is wise).

The question of what to do about the sections is indeed a stumbling
block to adding BLACKLIST and WHITELIST statements to the rules file.
Which is what I really prefer to do.

> 
> >> When 
> >> shorewall parses the blacklist file it generate rules for each 
> >> individual chain which has the "blacklist" option specified.
> >>
> >> 3. Scans for the "whitelist" option to determine the nature of the entry 
> >> - "DROP" if there isn't a "whitelist" option specified, "RETURN" if it is.
> >>
> >> 4. Generates the iptables code needed to be inserted later.
> >>
> >> One thing I did not account for here is inter-zone blacklists (say 
> >> vpn2net etc), but to my knowledge this is not currently implemented in 
> >> shorewall is it? If you do plan implementing that at a later stage, then 
> >> you may wish to scrap "src" and "dst" options and introduce two separate 
> >> columns for "SOURCE" and "DESTINATION" so that you determine where this 
> >> blacklist entry goes to - in a similar fashion as shorewall currently 
> >> does with the "rules" file.
> >>     
> >
> > I frankly wish I had taken a different approach when you talked me into the 
> > last set of blacklist changes. I don't want to compound that felony.
> >   
> I still can't see what the problem is? I mean, really, instead of 
> lumping all blacklisted statements into two shorewall-created chains 
> (blacklst and blackout) you will do it in separate, zone-independent 
> ones, and all the jumps to blacklst and blackout would be to 
> <zone>_blacklst and <zone>_blackout instead. Why is that not possible to 
> implement? Am I missing something obvious here?

See my first comment above.

Do you *really* need a zone name in the blacklist file, or would
specifying an interface meet your needs?

-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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