> > does- but this has drawbacks too as I mentioned....
> Exactly.... That's the job of a firewall Can you explain these "drawbacks" of
> using the firewall to do this....?
> From a performance/security viewpoint it's a very bad idea to let this get
> handled at application level. On Linux one has netfilter which does its job 
> and
> does it good and is properly tested and can be enhanced using extra
> modules.

Yes of course. The firewall does not know anything about the upper layer 
protocols and cannot filter based on a decision e.g. which Path is going tob e 
accessed or which virtual host. Which means we have to create different access 
locations for different user groups- this leads to a waste of IP adresses and a 
complication of the whole configuration. Of course I know that a firewall rule 
matching is way faster than a check on the application level but it can do 
less. E.g. you could also decide by IP range if a client is forced to use ssl 
or is redirected to another service or is forced to a backend which requires 
authentication and so on very easyly within an application level gateway. You 
are also able to show decent information tot he user why his/her access is not 
being granted right now. Performance of this checking is really no problem for 
us. We run a clustered pound setup with two virtual machines with each two 
virtual cpus. These are far away form being fully utilized let me say they 
could at least handle fifty times more users right now although they are doing 
ssl offloading and load balancing for around 10 portals with hundreds of users 
and although we already have a lots of rules with large regex sets within our 
configs.

I don't see the point why a application level gateway like pound should NOT 
feature such ip based filtering rule. You are still able to decide yourself if 
you want to use it and i fit meets your requirements or not- if you need the 
additional performance- decide to do it with your firewall.

Regards, Felix


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