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Re: Telco's write best practices for packet switching networks

  • From: Eric Brandwine
  • Date: Wed Mar 06 11:39:07 2002

>>>>> "rq" == Rob Quinn <[email protected]> writes:

>> When you've got a deployed server, run by clueful people, dedicated to a
>> single task, firewalls are not the way to go.

rq>  Probably.  And I would certainly rate "clueful people" _far_
rq>  above a firewall when it comes times to prioritize your security
rq>  needs and resources.

Mind having a talk with my management?

>> chose a resilient and flame tested daemon, and watch the patchlist for it.

rq>  You've never seen a security vendor come out with a patch or
rq>  workaround before an application vendor?

Sure.  Sometimes they come out with patches that wouldn't be needed if
you didn't have the firewall ;)

Stateful firewalls also suffer from state propagation problems.  High
bandwidth redundant links and firewalls don't get along well together.
Some firewall packages will allow you to statelessly pass high
bandwidth traffic (tcp,udp/53) in the DNS example, which helps with
load management and failover.  But then you're back to where you were
without the firewall.

Decent IDSes run on spanning ports against your uplinks, decent
logging on packet filtering routers, etc will all give you the
benefits of the firewall.  In general, and IDS is a better IDS than a
firewall, and so forth.

The primay benefit of firewalls is simplicity of configuration, and
the ability to allow outbound services without opening huge inbound
holes (tcp,udp/53, tcp/20, udp > 1023, etc).  This is generally not
the case with deployed ISP servers.

Finally, the "crunchy ouside" thing takes over way too often.
Management is lulled into a happy place by the word "firewall", and
even good security engineers get lazy.  I realize that this is 100% a
meat problem, but it's a problem either way.

Eric Brandwine     |  If people are good only because they fear punishment,
UUNetwork Security |  and hope for reward, then we are a sorry lot indeed.
[email protected]       |
+1 703 886 6038    |      - Albert Einstein
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