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Date:      Thu, 2 Jan 2003 14:33:34 -0500 (EST)
From:      Mike DeGraw-Bertsch <mbertsch@radioactivedata.org>
To:        Lucky Green <shamrock@cypherpunks.to>
Cc:        "doc@FreeBSD.ORG" <doc@FreeBSD.ORG>
Subject:   RE: IPFW: suicidal defaults
Message-ID:  <Pine.BSF.4.33.0301021431410.23590-100000@glow.usefulprojects.com>
In-Reply-To: <003901c2b294$9f341610$6601a8c0@VAIO650>

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Howdy,

While it's probably not the first place people look, if you look at the
firewall section in the LINT configuration, you'll see:

# WARNING:  IPFIREWALL defaults to a policy of "deny ip from any to any"
# and if you do not add other rules during startup to allow access,
# YOU WILL LOCK YOURSELF OUT.  It is suggested that you set
firewall_type=open
# in /etc/rc.conf when first enabling this feature, then refining the
# firewall rules in /etc/rc.firewall after you've tested that the new
kernel
# feature works properly.
#
# IPFIREWALL_DEFAULT_TO_ACCEPT causes the default rule (at boot) to
# allow everything.  Use with care, if a cracker can crash your
# firewall machine, they can get to your protected machines.  However,
# if you are using it as an as-needed filter for specific problems as
# they arise, then this may be for you.  Changing the default to 'allow'
# means that you won't get stuck if the kernel and /sbin/ipfw binary get
# out of sync.

So, without IPFIREWALL_DEFAULT_TO_ACCEPT, yep, you'll lock yourself out
right quick, even without an rc.conf change.  Not that I've done this
myself last week or anything. ;)

  -Mike

On Thu, 2 Jan 2003, Lucky Green wrote:

> Nick wrote:
> > 	Ummm, unless things have changed, just recompiling the
> > kernel with
> > 	'options IPFIREWALL' won't enable your firewall.  You need the
> > 	corresponding option in /etc/rc.conf :
> >
> > 		firewall_enable="YES"
> >
> > 	If you recompiled your kernel with 'options IPFIREWALL'
> > and didn't
> > 	enable the above switch in /etc/rc.conf then your problem isn't
> > 	the firewall blocking you.  Chances are your kernel won't load
> > 	properly on the machine the way you compiled it.
>
> I assure you that I didn't have firewall_enable="YES" set and yet the
> firewall was turned on once my system came back from reboot. Stock 4.6.2
> install, security branch cvsup. I am looking at rc.* this very moment.
>
> If I had enabled the firewall in rc.conf, I would richly deserve
> whatever punishment I got. :)
>
> One I finally got a hold of a guy on-site, his trying to use ping on the
> server make it pretty obvious that that firewall was active. He added an
> entry to rc.local that starts up the firewall with a more lenient rule
> set, but I will look at /etc/defaults/rc.conf to figure out how IPFW is
> supposed to be started up from rc.conf.
>
> I swear that the firewall came up without any changes to rc.conf,
> otherwise I wouldn't have emailed you folks in the first place...
>
> --Lucky
>
>
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