(I personally don't like bottom posting, but c'est la vie)
(see below :)

On Fri, 13 Feb 2004, Melvin Backus wrote:

> At 09:28 AM 2/13/2004, Christiaens Joachim wrote:
> > > -----Original Message-----
> > > From: David [mailto:maillist at ke6upi dot com]
> > > Sent: vrijdag 13 februari 2004 15:24
> > > To: Oliver Dumat
> > > Cc: m0n0wall at lists dot m0n0 dot ch
> > > Subject: Re: [m0n0wall] Problems with Dyndns update
> > >
> > > On Fri, 2004-02-13 at 02:52, Oliver Dumat wrote:
> > > > Hi,
> > > > we did testing some things and after the DSL connection was dropped
> > > > and monowall reconnects, the DynDns didn't get updated. After
> > > > resaving the Dyndns configuration, monowall updates the
> > > dyndns hostname.
> > > > So i think ez-ipupdate doesn't check, whether the ip of the
> > > WAN interface
> > > > is changed.
> > > > We use the actual (cdrom-pb27r630.iso) image.
> > > > Are we the only persons who have this problem?
> > > >
> > > > Greets,
> > > > Oliver Dumat
> > >
> > > I have a America Online account using PPPOE and it looks like we have
> > > the same problem. Could we have a cron job to force the
> > > update? Maybe a
> > > force time box on the page?
> > >
> > > David
> >
> >This will result in DynDNS blocking your account, because they don't like
> >updates giving the known address...
> >
> >Joachim
> 
> You can however check the ip in the script to verify that it is/isn't the 
> same as the last check.  If they match, do nothing, if the don't execute 
> whatever you like.  I used this setup to email my ip address to the office 
> any time it changed until I found out about dyndns.  This script from my RH 
> 7.2 machine worked great.  It ran once a minute.  The only quirky part is 
> it generated 2 emails, one when the link went down and another when it came 
> back up.  That actually turned out to give me an easy way to track outages 
> however.
> 
> ----------
> /sbin/ifconfig ppp0 | grep 'inet addr' >tmp2
> D=$(/usr/bin/diff -q tmp1 tmp2)
> case $D in
>          '') ;;
>          'Files tmp1 and tmp2 differ') cp tmp2 tmp1;elm -s IPChng office, 
> myemail at myisp dot com < tmp2 &>nul;;
> esac

I have my m0n0wall logging to my linux box which runs swatch with this in 
the config file:

===
watchfor = /.*ppp-linkup ng0 inet (\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}).*/
        exec="/root/bin/update_ip $*"
        echo 
===

/root/bin/update_ip is a shell script to compare the new IP with the old.
If it is different, the script will update remote DNS servers and send me 
a page. 

Conveniently, since migrating to m0n0wall, my IP only happens to change as 
often as I upgrade m0n0wall. 
I used to lose my PPPOE connection all the time with the linux rp-pppoe 
client.  yay m0n0!

-sharif