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Date:      Wed, 10 Dec 2003 20:39:28 -0500
From:      Barney Wolff <barney@databus.com>
To:        Andrea Venturoli <ml.ventu@flashnet.it>
Cc:        freebsd-net@freebsd.org
Subject:   Re: Two ISP connections
Message-ID:  <20031211013928.GA64700@pit.databus.com>
In-Reply-To: <200312110037.hBB0bpb6066726@soth.ventu>
References:  <200312110037.hBB0bpb6066726@soth.ventu>

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On Thu, Dec 11, 2003 at 01:37:52AM -0500, Andrea Venturoli wrote:
> ** Reply to note from Barney Wolff <barney@databus.com> Wed, 10 Dec 2003 11:39:00 -0500
> 
> 
> > I don't know of anything published that does this, but it's easy to 
> > write a perl or shell script that pings the router at the adsl isp 
> > and does the necessary things when it disappears and reappears.
> 
> Mmh, only problem is one of the ISP is famous for blocking ICMP as a whole, so no pings work. I haven't tried this
> particular line yet, but I may need to use come other protocol.

You can substitute anything that should get a response via isp1, and whose
result can be tested easily.

> > You start it from /usr/local/etc/rc.d (Hint - use nohup to keep it running). 
> Why nohup?

Things started from /usr/local/etc/rc.d get a hup signal when rc is finished
with all the startup scripts - I think.  Anyway, if you don't use nohup,
or a more-conventional way to daemonize what you've started, it will die
mysteriously in a very short time.  I've never seen anybody else use nohup
for this purpose but it works just fine on both 4.x and 5.x.

> > Without getting much fancier than is reasonable, existing connections 
> > will be dropped at switchovers. 
> 
> I can easily live with that.
> 
> > I have a script that does similar things running here; email me if you 
> > want it.
> 
> Why not! If you don't mind, the please send it to me :)

http://www.databus.com/dslsec.tgz
(FreeBSD lists don't allow attachments.)

Anyone is welcome to use/copy/modify these scripts.  For the two-isp
problem, if you're using NAT, you probably have to kill natd, reconfigure
it and restart it in the dslsec-gopri/gosec scripts.

-- 
Barney Wolff         http://www.databus.com/bwresume.pdf
I'm available by contract or FT, in the NYC metro area or via the 'Net.



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