DHCP on WAN problem - can I use static IP and call DHCP client with Cron?

[unguzov]

I have a big problem with some internet providers that insist on using DHCP on WAN. In pfSense 1.2.3 is common to not get IP address from DHCP server for hours for some reason.

It is impossible to get a static configuration from my ISP providers so it is possible to set a static IP and start dhclient with cron every hour - just to notice my provider to not stop my traffic if they do not get my DHCP request? This will change my WAN configuration and interrupt connection so it is possible to send just a DHCP request to my ISP, but not change my WAN settings?