remote nsupdate to set IP for PPP connection: caching problem

[schoppa]

Hi there,

via a ssh connection through a jailshell I update my nameserver at work when starting a PPP-Connection on Linuxbox at home. This works very fine. 

#!/bin/sh
LOCALIP=$4
C="echo -e \"update delete home.test.de\nupdate add home.test.de 300 A $LOCALIP\n\n\" | nsupdate"
ssh -t -l dyndns 1.1.1.1  $C    

A <nsupdate - nameserveratwork> shows, that the record in the zone has been updated. correctly.

BIG Problem: Foreigen nameserver are caching the updated zone file to long, so these namesevers have old IPs in their cache and not my current IP.

Could someone send me an example zonefile, that allows other nameserver caching the record/zone only for 10 Minutes. After that time the foreign nameserver should ask again my "nameserver at work" for the current IP.
In other words: how to set up a small version of dyndns.org on my own namerserver?

I tried several national Mailinglist, but no help

-- THANK YOU --
Marcus
(marcus.schopen at uni-bielefeld.de)