really simple dynamic dns notification?

[radagast]

hello helpful people.
i've set up a computer for my dad.
he likes it.
it's running vnc all the time so i can help him when all his icons disappear.
but he has a dynamic IP address (i don't), so i need to know what it is.

i've looked at the free dyndns-type services, but that seems like overkill when i just want to know the ip once a day.
i haven't installed any mail servers or clients, and setting all that up seems like overkill too.

my best idea is to make his machine ping mine whenever the ip address changes (how do i find that out?)
and catch those pings on my machine (probably there are a hundred ways to do that, but which?)

anyone got a really neat suggestion?

thanks,
andrew

[Sleipnir]

So if you know that the IP only changes once a day and you are able to get
the IP of the PC, I would suggest a cron job that copies the IP over to your
pc. Put somewhat like

[javeree_work]

Actually I would recommend dyndns for exactly this kind of application. To me the solution you're after sounds more complicated. Checking if the IP changes is also a thing that needs to be done if you're working with dyndns. I have used two methods.

My current method is logging on to my router using wget. A specific page on my router contains the IP address of the router, which I extract using grep/sed.

A previous method I used was getting http://www.whatismyip.com/ and also grepping the IP address.

The advantage of calling the router versus calling the webpage is that there is no guarantee that the source of the webpage will remain unchanged in the future => some maintenance to the grep expressions might be necessary.

The script that does this can be called in a cron-job. You will have to save the IP you get in a file in order to compare it and see if it has changed.

[Monkeh]

If you sign up for DynDNS, there are many free and open source updating clients available. It's not overkill, and is far easier than typing in an IP address every time you want to connection.

[PaulBredbury]

Set up a free account at dyndns, and emerge ddclient

In /etc/ddclient/ddclient.conf:

[radagast]

thankyou everyone,
and thankyou Sleipnir for the elegant solution i was looking for.

his computer writes it's address by scp to my server,
i connect with a line like

[xanthax]

The command to get your ip is:

[crazyweber]

i was looking to configure ddclient. all was going will till i had to modify /etc/ppp/ip-up.local and /etc/ppp/id-down.local. My /etc/ppp folder doesn't exsist. Is there something else I must install or is it safe to create these files?

[Katphish]

[blob2004]

I emerged ddclient, then I checked out the init script for ddclient:

$ cat /etc/init.d/ddclient
#!/sbin/runscript
# Copyright 1999-2004 Gentoo Foundation
# Distributed under the terms of the GNU General Public License v2
# $Header: /var/cvsroot/gentoo-x86/net-dns/ddclient/files/ddclient.rc6,v 1.4 2004/07/14 23:21:59 agriffis Exp $

depend() {
need net
}

checkconfig() {
if [ ! -e /etc/ddclient/ddclient.conf ] ; then
eerror "You need a /etc/ddclient/ddclient.conf file to run ddclient"
eerror "There is a sample file in /etc/ddclient/"
return 1
fi

}

start() {
checkconfig || return 1
ebegin "Starting DDClient"
start-stop-daemon --start --quiet --exec /usr/sbin/ddclient
eend $?
}

stop() {
ebegin "Stopping DDClient"
start-stop-daemon --stop --quiet --pidfile /var/run/ddclient.pid
eend $?
}

Then I started it:

$ sudo /etc/init.d/ddclient start
[ ok ]ing DDClient ...

But there is no ddclient.pid file:

$ sudo ls /var/run/ddclient.pid
ls: /var/run/ddclient.pid: No such file or directory

Which at least means that I can't stop it:

$ sudo /etc/init.d/ddclient stop
[ !! ]ing DDClient ..

Also, after starting, it doesn't seem to be running:

$ sudo /etc/init.d/ddclient start
[ ok ]ing DDClient ...


$ sudo pgrep dd
$

Although it thinks it is!

$ sudo /etc/init.d/ddclient status
* status: started

Anyone know what's up with this? is it really started and running?