There are a few ways to go about this.
1)You can run a stripped down (running minimal and only required services)
Linux box serving only SSH connections and you can use that machine to login
into your PIX (allowing your PIX to only accept connections from this SSH
server) and perform administration.
2) Or...you can just run the PIX and I think you can also run a TACACS+
server with it to authenticate encrypted passwords and logins, or run
encryption on the PIX itself. I could be mistaken, but I know something
like that would probably work best.
But the thing that people have to understand is, that *no one* can
absolutely guarantee that anything can't be compromised. It will always be
a 99.999....% chance that it will be secure. It all depends on how the
firewall you choose is set up. Anything is breakable.
But in my opinion, I would recommend running a hardware firewall solution
such as the PIX or equivalent because the device is specifically made to run
the firewalling processes. Unlike a Linux/Unix/NT box with a software-based
firewall system such as Checkpoint, etc. a hardware solution does not have
the OS overhead with services that firewalling does not require and also
exploits and patches that you need to constantly be up to date about, issues
that others have already mentioned. It just comes down to how much money
you want to spend and also what you prefer. I may prefer the Cisco PIX, but
I have friends that recommend a home-grown Unix box solution.
Just trying to help,
Roger
----- Original Message -----
From: "Sean Young" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>; <[EMAIL PROTECTED]>; <[EMAIL PROTECTED]>;
<[EMAIL PROTECTED]>
Sent: Monday, March 26, 2001 12:42 PM
Subject: Re: Performance Comparision between Linux OS Firewall and Cisco PIX
525
> Allen,
> If SSH service is not open on the outside interface, how do you expect
> to troubleshoot the problem when there is problem with the Firewall?
> Tell me this, how can you troubleshoot a PIX remotely when there is
> problem? My employer is certainly not going to fly me out-of-state to fix
a
> minor problem. Furthermore, can you absolutely guarantee me, in writing,
> that the Cisco PIX
> can never be compromised? Another thing, what makes you think that I am
> also running other services besides Firewall features on Linux. If you
> read my email carefully, you also notice that I only SSH and netfilter
> (aka iptables) on the Firewall. Your reason is based purely on FUD
> (Fear, Uncertainty and Doubt).
>
> Sean
>
>
> >From: "Allen May" <[EMAIL PROTECTED]>
> >To: "Sean Young" <[EMAIL PROTECTED]>, <[EMAIL PROTECTED]>,
> > <[EMAIL PROTECTED]>, <[EMAIL PROTECTED]>
> >Subject: Re: Performance Comparision between Linux OS Firewall and Cisco
> >PIX 525
> >Date: Mon, 26 Mar 2001 14:29:34 -0600
> >
> >Is the outside interface still open to SSH connections? If so & it's
> >compromised, Linux is a full blown operating system that, when
compromised,
> >can have ANY program designed for Linux installed. Can you imagine
> >something like a packet analyzer grabbing all your passwords and sending
> >them out over the net to someone else? Ewww. That's my #1 reason for
> >going
> >with something like a PIX. Just make sure you're IDS is set to notify
even
> >in the event of a SUCCESSFUL connection. I've seen people who set it up
> >for
> >unsuccessful attempts only.
> >
> >I hope that guy wasn't fired BECAUSE he recommended the Cisco solution.
> >That's totally a matter of point of view on that decision & his wasn't
> >wrong..neither was the Linux choice. Some situations call for one while
> >others call for the other.
> >
> >Oh and keep a copy of the correctly configured drive with all settings on
> >hand. A hard drive is much more prone to failure than RAM/ROM just due
to
> >the moving parts involved.
> >
> >Allen
> >----- Original Message -----
> >From: "Sean Young" <[EMAIL PROTECTED]>
> >To: <[EMAIL PROTECTED]>; <[EMAIL PROTECTED]>;
> ><[EMAIL PROTECTED]>
> >Sent: Sunday, March 25, 2001 3:05 PM
> >Subject: Re: Performance Comparision between Linux OS Firewall and Cisco
> >PIX
> >525
> >
> >
> > > Ken,
> > > Thank you very much for the advice. This past Friday, my company has
> > > decided to use Linux as our company Firewall. Furthermore, we've
> >decided
> > > that this Firewall will be running kernel 2.4.2 with only two services
> > > running on it, SSH and netfilter (aka iptables). I've tested kernel
> > > 2.4.2 in the lab and notice it performs better than kernel 2.2.x.
I've
> >also
> > > performed various intrusion detection tests on the box using
> > > Cisco NetSonar, Cybercop, ISS, Axent Netrecon but is unable to break
> > > it. The linux box is rock-solid. I am also running portsentry (IDS)
> > > on the Firewall itself.
> > >
> > > Also, we decide to running our squid proxy server on another linux box
> > > to provide transparent caching for our internal users. As far as VPN
is
> > > concerns, we are going to implement FreeS/WAN on another box. I think
> > > in the long run, it is going to save the company a lot of money. We
> > > end up not buying the PIX and web-caching engine from Cisco. Oh, the
> > > networking guy in our group who recommends Cisco PIX and Cisco web-
> > > caching engine as a solution, he has been fired. Go figure.
> > >
> > > Regards,
> > > Sean
> > > P.S. Priscilla, why not implementing TRANSPARENT caching by using
squid
> > > to speed up internet connection for your users? Squid is free and
very
> > > secure and easy to use.
> > >
> > > >From: [EMAIL PROTECTED]
> > > >Reply-To: [EMAIL PROTECTED]
> > > >To: [EMAIL PROTECTED], "Stuart Brockwell"
> ><[EMAIL PROTECTED]>
> > > >Subject: Re: Performance Comparision between Linux OS Firewall and
> >Cisco
> > > >PIX 525
> > > >Date: Sat, 24 Mar 2001 20:02:26 -0800
> > > >
> > > >Sean,
> > > >
> > > >Comments imbedded:
> > > >
> > > >On 23 Mar 2001, at 16:12, Stuart Brockwell wrote:
> > > >
> > > > > Hi Sean,
> > > > > I am a Linux head my self, and one of our firewalls is in
fact
> > > > > running
> > > > > on a Linux box. The only problem with this type of firewall is
that
> > > > > you inherit all of the known bugs that the software has. Given
that
> > > > > the source code to Linux is widely available, you have a lot of
very
> > > > > talented people out there who know these holes and are able to
> >exploit
> > > > > them very easily.
> > > >
> > > >It also means that there are a lot of talented people who are looking
> > > >at the code to make sure that any holes are patched. In fact, when
> > > >new exploits are found, Linux is usually the fastest platform to have
> > > >a patch available. Compare this to having to wait weeks for vendor
> > > >patches or having to prove to a vendor that a problem exists.
> > > >
> > > >Also, a service can only be exploited if it is running. A properly
> > > >configured firewall doesn't run unecessary services, this makes it
> > > >very difficult to exploit. Essentially, it would come down to trying
> >to
> > > >DoS it or running a password guessing program against it to get
> > > >remote access.
> > > >
> > > >
> > > > If you
> > > > > maintain your own Linux firewall, you will need to continuously
look
> > > > > for the latest bug fixes to install on your Linux box to address
the
> > > > > latest round of holes that have been released.
> > > >
> > > >If the Linux firewall is properly setup, the only services running on
> >it
> > > >are ipchains and SSH. This means that you have to be aware of 2
> > > >services. While there could always be a local exploit, if only
> > > >trusted admins have access, the trouble with keeping up patches
> > > >is minimal. It is certainly no more trouble than keeping up with
> > > >bugs on a vendor platform.
> > > >
> > > > >
> > > > > Cisco and companies such as Watch Guard closely guard their source
> > > > > code, often you can elect to take on a maintenance contract with
the
> > > > > firewall where you recieve all the latest fixes for a 12 month
> >period
> > > > > (this is what we did). As this is their bread and butter, they
> >spend
> > > > > a lot of time looking for holes and fixes to known bugs.
> > > > >
> > > >
> > > >While true, this doesn't mean that their code will have fewer bugs
> > > >or that the bugs will be patched quicker. There is a very large
> > > >support community for Linux that is very technical. Most bugs are
> > > >patched in a matter of days, sometimes hours.
> > > >
> > > >
> > > > > the main plus for each of
> > > > > the commercial packages is that there is large support base, where
> >as
> > > > > skilled Linux admin staff who can lock down a firewall are very
few
> > > > > and far between.
> > > >
> > > >This is simply not true. There is a very large community of Linux
> > > >developers and admins, and most of them are very knowledgable.
> > > >There are good mailing lists and _plenty_ of good Linux
> > > >security/firewall books, articles, web sites, etc. available.
> > > >
> > > >Locking down a Linux box is not rocket science. That is FUD that
> > > >is propagated by vendors who want to sell product. It's not hard to
> > > >configure a Linux box to be secure, the difficulty comes in running
> > > >lots of services and providing access to users. If you have a box
> > > >that runs web, ftp, smtp, nfs, etc., then it becomes much harder to
> > > >secure, but none of these services should be running on a firewall.
> > > >
> > > >The bottom line is that there are several good commercial firewalls,
> > > >but that doesn't mean that a Linux box cannot serve as a good, low-
> > > >end alternative. Especially if cost is one of the main decision
> > > >factors.
> > > >
> > > >-Kent
> > > >
> > > >
> > > >
> > > >
> > > >_________________________________
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