Udpate my ip on ubuntu system

Udpate my ip on ubuntu system

install lynx
>sudo apt-get install lynx

add to automatic startup
>su root
>vi /etc/rc.local

add one line:
lynx -mime_header -auth=username:password "http://www.3322.org/dyndns/update?system=dyndns&hostname=sillycat.3322.org"

But this way may not work.

>cp proxy.sh ipproxy.sh
>vi ipproxy.sh
#!/bin/sh

lynx -mime_header -auth=username:password "http://www.3322.org/dyndns/update?system=dyndns&hostname=sillycat.3322.org"

then I can execute this command in the future.
>ipproxy.sh