Yes, I'm in a sarcastic mood. I get that way when I see 
uninformed assertions. You've been warned.

Diederik Schouten wrote:
> 
> Bridged firewalls do not need subnet based address assignment on 
> their interfaces, you can have 10 interfaces with technically
> overlapping IP address ranges on all. 
>
> When you have to add the firewall to an already existing network, 
> you do not need to reconfigure any other device on the network, 
> your addressing schemes and routing stays exactly the same, the 
> only downtime you will have is due to the fact that you have to 
> connect the cabels

This is impossible with a routing firewall?
Dzang, I must have only dreamed us doing that for all these years.
[And all the other boxes doing that I don't remember right now]

> Similar situations will require vast/intelligent routing on 
> a routed firewall

  Iface  Destination
  -----  -----------
  eth0   10.0.0.0/8
  eth1   10.0.0.5-10.0.0.8
  eth2   10.0.1.0/24, -10.0.1.88
  vlan5  10.0.0.15, 10.0.0.18, 10.0.0.20-10.0.0.25

Yeah, in our case, we needed to implement half an AI to get that 
to work. Took all of about an afternoon.


> Link redundance without session loss is also extremely easy to 
> setup using a bridged firewall

Hm I must also have been dreaming when I added those HA slaves
with <1 second failover time. Using non-bridging firewalls.
With less than five minutes of work per cluster (sans hardware 
install time, of course).


> It will not show up as a gateway anyware. 

Hm. Enable proxy arp on the internal interface for the entire
default route. Problem solved -- it'll look like an L4 switch.


> Traceroutes won't show it is there etc.

Blocking traceroute isn't exactly rocket science.
A determined firewall aims at blocking _firewalking_, plus
variations thereof, by default. Are you suggesting that 
this won't stop that measly traceroute?


> Unless you know it's IP address already you will not be able 
> to find it.

Nmap will tell me it is there in about 10 seconds. I betcha its
signature sticks out like a sore thumb too.


> Putting multiple firewalls in series to create for example more 
> ports becomes very easy, although for example with the Lucent BRICK 
> this is not necesary since it supports VLAN tagging and with a VLAN 
> capable switch you can create virtually any number of "virtual" 
> firewalls you might need, and give them all their own ruleset.
> No need for recabling and expensive upgrades

Jeez. I was wrong about VLAN support in routing firewalls too.

And only using VLANs must be a SUPERIOR way of adding more interfaces. 
Especially given the "VLANs and security" thread going on right now.


> a purpose build firewall does not depend on the operating system of 
> the router/platform it is running at, lowering the chance of being 
> penetrated due to bugs in code other than for the firewall

Although I agree 100% with what you are saying here, I cannot
for the life of me grasp how this constitutes a "pro" for a bridged 
firewall over a routing firewall.



In summary: you haven't convinced me in any way that a bridging
firewall has a single security advantage (or even a management 
advantage) over a routing firewall.


-- 
Mikael Olsson, Clavister AB
Storgatan 12, Box 393, SE-891 28 �RNSK�LDSVIK, Sweden
Phone: +46 (0)660 29 92 00   Mobile: +46 (0)70 26 222 05
Fax: +46 (0)660 122 50       WWW: http://www.clavister.com
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