Date: Wed, 28 Feb 2007 21:16:41 +0000 From: RW <fbsd06@mlists.homeunix.com> To: freebsd-questions@freebsd.org Subject: Re: pf.conf and cable modem Message-ID: <20070228211641.68c06f16@gumby.homeunix.com> In-Reply-To: <20070228131913.y8awi6yt74c88084@mail.schnarff.com> References: <200702272248.l1RMmD81013215@cheyenne.sixcompanies.com> <8cb6106e0702271455w5be91292vfce007b8ed439e1d@mail.gmail.com> <20070228173517.5a044300@gumby.homeunix.com> <20070228124421.j73ex8x4ow0g0o8k@mail.schnarff.com> <20070228180215.03fcd926@gumby.homeunix.com> <20070228131913.y8awi6yt74c88084@mail.schnarff.com>
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On Wed, 28 Feb 2007 13:19:13 -0500
alex@schnarff.com wrote:
> Quoting RW <fbsd06@mlists.homeunix.com>:
>
> > On Wed, 28 Feb 2007 12:44:21 -0500
> > alex@schnarff.com wrote:
> > I was using a half-bridge modem that had a 30 second lease time,
> > which was definitely renewing. It would also give me a private
> > address when PPPoA went down, and I saw that happen too.
>
> Are you sure it was a 30 *second* lease time? No sane ISP would set
> such a low value -- that's a surefire way to overwhelm their DHCP
> servers.
As I said, it was a half-bridge modem. It terminates PPPoA and delivers
the public IP address and DNS server addresses with its own DHCP
server. When PPP is not connected it issues a private IP address
instead.
Until the Draytek Vigor 100 offered true PPPoA to PPPoE bridging,
half-bridge modems were the only ethernet-based modems that would work
with FreeBSD and PPPoA.
> > I added-in some early static rules to log all the DHCP packets.
> > IIRC I never saw any of the lease renewal packets, just some
> > broadcast packets. I asked in this list about it but never got a
> > reply.
>
> What were the rules? I'd be curious to see them.
>
pass out log quick on $ext_if proto udp from port { bootps, bootpc} to port { bootps, bootpc}
pass in log quick on $ext_if proto udp from port { bootps, bootpc} to port { bootps, bootpc}
I can't remember the details, but the only packets I saw with tcpdump
were some incoming broadcasts from the DHCP server.
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