I had a special requirement from a customer.. to allow him into his linux box even though he may be sourcing from a random ip address
– customer will create a dyndns.org account and run the dyndns updater from his laptop. this will auto update dyndns of his current ip
– server will run a dynamic firewall script via cron which will periodically resolve his myname.dyndns.org to the current ip, and the server will then update its iptables rule accordingly.
I found this script from Dave Horner very useful… jump here. I’ve modified his script a little so the customer can access only specific ports into the server (ssh, ftp, vnc & web)