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* Netfilter vs commercial
@ 2004-08-09 15:30 Michael Gale
  2004-08-09 15:56 ` Antony Stone
                   ` (2 more replies)
  0 siblings, 3 replies; 17+ messages in thread
From: Michael Gale @ 2004-08-09 15:30 UTC (permalink / raw)
  To: netfilter

Hello,

	I know this question has most likely come up a few times and most people ask about performance and through put. But my
question seems to me a little different.

I would like to know how people on this list ... which I know might be a biased opinion feel how a Netfilter firewall
box .. properly configured would compare in security to a commercial firewall. 

I do not want to compare performance or stats on through put but the strength of the firewall. The reason I am asking is
to at the moment we are using Netfilter based firewalls which I have setup Squid and Frox and many other application
level filters.

Now some people in the company want to replace them with CheckPoints or WatchGuard firewalls. Which is fine ... security
should be done in layers ... but the way I see it I will still need the linux boxes to run squid and frox unless the
appliance allows you to install software from other sources (most likely not) or use custom config files (like my own
squid.conf -- most likely not).


-- 
Michael Gale
Network Administrator
Utilitran Corporation


^ permalink raw reply	[flat|nested] 17+ messages in thread
* RE: Netfilter vs commercial
@ 2004-08-09 16:34 Jason Opperisano
  0 siblings, 0 replies; 17+ messages in thread
From: Jason Opperisano @ 2004-08-09 16:34 UTC (permalink / raw)
  To: Michael Gale, netfilter

>
> I would like to know how people on this list ... which I know might be a biased opinion feel how a Netfilter firewall
> box .. properly configured would compare in security to a commercial firewall.

it would be equivalent--given that both firewalls are configured by "experts."  the majority of my day job involves check point fw-1/vpn-1 consulting.  as far as "firewall filtering capabilities" (for lack of a a better term), you can build a firewall using netfilter that has at least the same; if not more, functionality as fw-1/vpn-1.  the path of a packet through the fw-1 kernel (from memory--don't quote me on this):

- drop all packets with IP Options set
  netfilter:  "-m ipv4options --any-opt -j DROP" -OR- "-j IPV4OPTSSTRIP"

- drop spoofed packets (anti-spoofing)
  netfilter:  easy enough to setup with iterations on "-s $INTERNAL_NET -i ! $INTERNAL_IF -j DROP" etc...

- if packet is not "new" compare to state table
  netfilter:  use "-m state --state ESTABLISHED,RELATED" to allow replies to established connections 

- if packet is "new" compare to security policy rule base
  netfilter:  use "-p tcp --syn -m state --state NEW -j ACCEPT" to accept new connections (for TCP at least)
>
> I do not want to compare performance or stats on through put but the strength of the firewall. The reason I am asking is
> to at the moment we are using Netfilter based firewalls which I have setup Squid and Frox and many other application
> level filters.

beyond basic stateful filtering--you can enable higher-level security checks using application-level gateways as you are currently doing.  check point refers to this as "application intelligence" which allows you to do things like blocking user-agent strings in HTTP communications.  there's is absolutely *nothing* that check point can do here that you can't do with squid.  conversely--there's plenty you can do with squid that you cannot do with application intelligence.  check point point to the fact that the application intelligence checks run in-kernel as opposed to user space, which i'm sure is much faster.  not sure if the speed difference is actually relevant though.  my experience with this has been that application intelligence gives people just enough capability to make them really want a true, full-blown application level gateway--which is precisely what check point has argued against since its inception.

check point's real selling point is in their management architecture--the ability for a security admin that either lacks the time or expertise to manage rulebases on many firewalls (100's) with a suite of pretty GUI management applications (rule editor, log viewer, status viewer).  if you have just a few firewalls, and are competant with shell/perl scripting--you could be much happier managing your firewalls through an SSH connection.

if you really know what you're doing and have very specific filtering goals in mind--you'll probably be happier with netfilter in the long run, as it will allow amazingly granular control of how/when/why packets get filtered.

dunno if this helps, but i'm also not sure that the question isn't just a wee bit too high in flame-bait content (i understand you didn't intend it as such).

-j


^ permalink raw reply	[flat|nested] 17+ messages in thread
* Re: Netfilter vs commercial
@ 2004-08-09 16:48 Mike O
  2004-08-09 17:03 ` Antony Stone
                   ` (2 more replies)
  0 siblings, 3 replies; 17+ messages in thread
From: Mike O @ 2004-08-09 16:48 UTC (permalink / raw)
  To: netfilter

John,

Would you mind elaborating on your comment about Netfilter's stateful engine 
being weaker than Checkpoint's? and how would the window tracking patch make 
it more secure. We have checkpoint here and have ran into problems, where 
checkpoint has limited us in the way we do things here and I have always 
wanted to implement netfilter but couldn't because it's open source.

Thanks,

Mike


>From: "John A. Sullivan III" <jsullivan@opensourcedevelopmentcorp.com>
>To: Michael Gale <michael.gale@utilitran.com>
>CC: netfilter@lists.netfilter.org
>Subject: Re: Netfilter vs commercial
>Date: Mon, 09 Aug 2004 12:02:52 -0400
>
>On Mon, 2004-08-09 at 11:30, Michael Gale wrote:
> > Hello,
> >
> > 	I know this question has most likely come up a few times and most 
>people ask about performance and through put. But my
> > question seems to me a little different.
> >
> > I would like to know how people on this list ... which I know might be a 
>biased opinion feel how a Netfilter firewall
> > box .. properly configured would compare in security to a commercial 
>firewall.
> >
> > I do not want to compare performance or stats on through put but the 
>strength of the firewall. The reason I am asking is
> > to at the moment we are using Netfilter based firewalls which I have 
>setup Squid and Frox and many other application
> > level filters.
> >
> > Now some people in the company want to replace them with CheckPoints or 
>WatchGuard firewalls. Which is fine ... security
> > should be done in layers ... but the way I see it I will still need the 
>linux boxes to run squid and frox unless the
> > appliance allows you to install software from other sources (most likely 
>not) or use custom config files (like my own
> > squid.conf -- most likely not).
>
>It's a difficult question to answer without access to the internals of
>the proprietary products.  I would assume the basic stateful inspection
>engine of netfilter is weaker than that of Checkpoint.  However, this
>may very well be remedied when one adds the window tracking patch.
>
>Other internals remain a bit of a mystery.  For example, if I remember
>correctly, one can specify MSRPC as a protocol with Checkpoint and it
>will properly handle the port shift.  One the other hand, one cannot do
>this in netfilter.  One must open 135/tcp and then all high ports.  Yes,
>I know that one should never do this on the Internet but what about
>internal firewalling and VPN firewalls.  Now it could very well be that
>is all Checkpoint does but they've simplified it in the user interface.
>I do know that we have had to do that with other commercially available
>firewalls.
>
>There are two other important issues of security that do not necessarily
>relate to the actual internals.  One is how well the management
>interface shields one from human error.  For example, this is one of the
>chief advantages of the ISCS interface for netfilter
>(http://iscs.sourceforge.net).  Not only does it reduce the time to
>configure security by over 90% but it dramatically reduces the exposure
>to human error.  Unfortunately, it has not yet been released.  On the
>other hand, from what I recall, the WatchGuard and Checkpoint interfaces
>are really just GUI rule configurators and do little to insulate the
>administrator against human error (such as putting a rule in the wrong
>order or making it conflict with another subsystem like NAT or VPN).  I
>believe all of the other user interfaces for netfilter also fall into
>this rule configurator category.
>
>Finally, there is the degree of control.  This is where netfilter has a
>distinct advantage.  The degree of flexibility that one has to configure
>netfilter to do exactly what one wants it to do by command line or
>script or even editing the source code is outstanding.  One can also
>tinker with the related subsystems such as iproute2 or *swan to
>coordinate various security and network activities to an extraordinary
>level.  I do not recall such flexibility in other products.
>
>I do hope this is the type of answer you were looking for - John
>--
>John A. Sullivan III
>Open Source Development Corporation
>Financially sustainable open source development
>http://www.opensourcedevelopmentcorp.com
>
>




^ permalink raw reply	[flat|nested] 17+ messages in thread
* RE: Netfilter vs commercial
@ 2004-08-09 18:24 Jason Opperisano
  2004-08-09 18:40 ` Antony Stone
  2004-08-11 21:40 ` Aleksandar Milivojevic
  0 siblings, 2 replies; 17+ messages in thread
From: Jason Opperisano @ 2004-08-09 18:24 UTC (permalink / raw)
  To: netfilter

> Sure, although it may reflect more of my ignorance than my sagacity :-)
>
> >From what I understand, the out of the box netfilter connection tracking
> sets timers for the dataflow and matches source and destination
> information and, for TCP, session states.  It does not match the
> acknowledgment and sequence numbers for TCP packets unless one adds the
> window tracking patch.  Someone please correct me if I am wrong.
>
> I cannot say so authoritatively but I believe out of the box Checkpoint
> does match ACK and SEQ - John

"out-of-the-box" check point fw-1 does not track seq/ack numbers.  the
"sequence verifier" can be enabled if one chooses to; however, it is
mutually exclusive with some other features (such as their connection
acceleration feature).  i meant to mention the tcp-window-tracking patch for
netfilter in my original reply.

just to reiterate--as far as responses to, "oh yeah?  well can your firewall
do this?" questions go--netfilter can hold up to check point extremely well.
maybe if the OP has some specific issues the higher-ups need addressed--we
can answer those in a new "can netfilter do X" thread.

and as an aside--i find it hard to believe that there are people out there
saying something along the lines of "we use commercial software becuase we
can sue the manufacturer if it breaks."  i know no one actual reads those
EULA's that are presented at install time--but they say "if this software
breaks, you can't sue us."  where was that big lawsuit against microsoft for
damages resulting from <insert favorite ms exploit here>?

-j

ps - IANAL


^ permalink raw reply	[flat|nested] 17+ messages in thread

end of thread, other threads:[~2004-08-11 22:11 UTC | newest]

Thread overview: 17+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2004-08-09 15:30 Netfilter vs commercial Michael Gale
2004-08-09 15:56 ` Antony Stone
2004-08-09 16:02 ` John A. Sullivan III
2004-08-11 21:46   ` Aleksandar Milivojevic
2004-08-11 22:11     ` John A. Sullivan III
2004-08-11 21:31 ` Aleksandar Milivojevic
  -- strict thread matches above, loose matches on Subject: below --
2004-08-09 16:34 Jason Opperisano
2004-08-09 16:48 Mike O
2004-08-09 17:03 ` Antony Stone
2004-08-09 17:35   ` John A. Sullivan III
2004-08-09 18:15     ` Antony Stone
2004-08-11 21:31   ` Aleksandar Milivojevic
2004-08-09 17:39 ` John A. Sullivan III
2004-08-09 17:45 ` John A. Sullivan III
2004-08-09 18:24 Jason Opperisano
2004-08-09 18:40 ` Antony Stone
2004-08-11 21:40 ` Aleksandar Milivojevic

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