Date: Tue, 13 Jul 1999 22:16:32 +0930 (CST) From: Kris Kennaway <kkennawa@physics.adelaide.edu.au> To: Stephen Hocking-Senior Programmer PGS Tensor Perth <shocking@prth.pgs.com> Cc: hackers@freebsd.org Subject: Re: Setting up a firewall with dynamic IPs Message-ID: <Pine.OSF.4.10.9907132210380.2013-100000@bragg> In-Reply-To: <199907130856.QAA12434@ariadne.tensor.pgs.com>
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On Tue, 13 Jul 1999, Stephen Hocking-Senior Programmer PGS Tensor Perth wrote:
> I was checking out the firewall setup in /etc/rc.firewall, and noticed that
> the simple example relied on a fixed IP address for the external interface. I
> don't know ahead of time what IP address is going to be allocated to me before
> I dial up. Would it be possible to specify an interface (tun0) rather than an
> IP address?
You could probably do it from /etc/ppp/ppp.linkup, which knows your IP address
as MYADDR. But if you just have asingle machine on the end of the dialup then
I find I can get away with just specifying the netmask from which the dialup
IPs are assigned in place of a single address - all that can happen is that
packets get through your firewall destined to a nonexistent address (i.e. if
you allow incoming port Y traffic then people can send to port Y on
nonexistent IP addresses (i.e. your peer addresses) which will be dropped by
the kernel).
Kris
-----
"Never criticize anybody until you have walked a mile in their shoes,
because by that time you will be a mile away and have their shoes."
-- Unknown
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