DHCP dynamic IP address

[JJB]

I have 24/7 cable connection to public internet and get dynamic IP
address assigned by ISP.
Problem is now that I have started to stay connected 24/7 my dynamic
IP address has not changed in 5 weeks and all the script kiddies are
beating on my firewall front door.
I now want to make my self harder to be found by the script kiddies.
When I was powering off my PC and cable modem every night I did not
have this problem because I was getting an different
dynamic IP address every day.

I use the FBSD built-in DHCP client to get my IP address
and lease renewal.

I would like to know if there is some DHCP client option to tell my
ISP at lease renewal time to force the issuing of an
different dynamic IP address?

Thanks in advance