On 13/03/13 15:24, Tom Eastep wrote:
> On 03/13/2013 04:45 AM, Mr Dash Four wrote:
>>> 10) 'blackhole' routes are now copied to provider tables when
>>>     USE_DEFAULT_RT=No. Previously, these routes were not copied with
>>>     the result that packets could be routed to blackholed addresses.
>>>
>>> [...]
>>>
>>> 6)  'blackhole' routes may now be defined in /etc/shorewall[6]/routes.
>>>     Simply place 'blackhole' in the GATEWAY column and leave the DEVICE
>>>     column empty.
>>>   
>> For anyone (myself included) using this approach, be aware of the following:
>>
>> When a network interface goes down, all routes defined for that 
>> interface simply disappear, *except* the blackhole routes! What this 
>> means in reality is when the interface goes back up again, the previous 
>> routes, which were added when shorewall was brought 
>> up/loaded/reloaded/restarted need to be re-defined somehow (see below), 
>> otherwise all subnets defined as "holes" in those blackhole routes will 
>> *not* be reachable!
>>
>> I have just fallen, again, into this trap and spent the best part of 
>> this morning clearing up the mess, simply because I forgot to add these. 
>> There are, as far as I know, two approaches for solving this problem:
>>
>> 1. In addition to the "standard" shorewall package (shorewall-lite, 
>> shorewall, etc), add shorewall-init to take care of this (Tom, I am 
>> certain that the routes defined in those files will be honoured by 
>> shorewall-init, could you confirm this please?);
> Yes.
>
>> 2. Add all network-interface dependent routes (the ones which 
>> "disappear" when the interface goes down) to 
>> /etc/sysconfig/network-scripts/route-X (where "X" is the name of the 
>> interface in question). At least in Fedora's case, these can be taken 
>> care of by using the *new* format (which is the "ip" command format, 
>> i.e. "ip route add ..."). For example - to add a route to 10.1.0.0/24 
>> via 10.1.1.1 on eth0 using table dmz, the following needs to be added to 
>> /etc/sysconfig/network-scripts/route-eth0:
>>
>> 10.1.0.0/24 via 10.1.1.1 dev eth0 table dmz
> Again, shorewall-init will trigger an 'up' command for the interface
> which reloads all routes for the interface that were originally loaded
> by start/restart.
>
>> That way, when the eth0 interface goes up, the above route will be 
>> "automatically" defined by the OS.
>>
>> Tom, I am not sure whether there is a page on shorewall.net, which 
>> explains all this, but if it isn't I think it is worth adding one as I 
>> can imagine I am not the only one who would fall in the above trap. I am 
>> willing to give it a go for the writing bit, if you prefer - just let me 
>> know.
>>
> There is no single place where these points are explained. I also notice
> that the tables in http://www.shorewall.net/Shorewall-init.html are out
> of date. For optional interfaces, shorewall-init now triggers 'enable'
> and 'disable' operations rather than reloading the configuration.
>
> I think that article would be a good place to gather all of this
> information in one spot. If you agree and would like to give it a go, I
> would be grateful.
>
> Thanks,
> -Tom
>
>
>
>
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I think our mails must have crossed in a que somewhere as your comment
there seems to confirm my suspicion that shorewall disable and a later
shorewall enable would have the same effect was looking for a solution
other than the given example with the data duplication issue.

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