Hello All,

I have bought a domain mystware.co.uk and want to host myself. I can use the domain services software to point the domain to an I.P. Address - its currently pointing at bbc.co.uk.

My ISP assigns my external IP address via DHCP, therefore it could change. To stop this from happening I want to run a cron command to renew the external IP every six hours so theres no chance of losing the IP thus it would be safe for me to point my domain to the external IP for my set-up.

I have seen posts refering to dhclient but I have a feeling this would change my internal IP address and not the external one. I am completely new to this so I would appreciate as much help as possible.

The following info about my system may be relevant

Current External IP:82.6.77.187

Router IP: 192.168.11.1
Server IP: 192.168.11.101 (Static)

As you say, I don't believe dhclient will help in this case, since the dchp client is the router.
Check your router manual, there are settings on some that will allow the router to maintain the 'lease' indefinitely and keep the ip from being recycled by dhcp. A combination of this and a ping heartbeat at intervals to convince the router you are still active may work indefinitely.
Isp's are in the business of charging significantly more for static ip, so it is likely they will find a way to end the party, but you never know.

To get that done you'll need a Dynamic DNS service. Google around for some Dynamic DNS serivce providers (aka DynDNS or DDNS). Here's the link to what the one i'm using:
http://www.changeip.com/
Once you get it going, you'll some clients and scripts which you can run as a cron job to keep things going smooth.

One final note: The ChangeIP service can take up to 5 mins to refresh the dns records, so if you set the updating script on your machine to run every 5 minutes, then you're looking at a worst-case scenario of being offline for 10 mins each time the IP changes.