Processes run by rails ignore SIG_TERM

Hello Everybody,
it happens that my Rails 1.2.5 application developed in Linux
environment starts DHCP service (version 3.0.1-r1 taken from
www.isc.org/products/DHCP).
After that the process run in his turn by the service (dhcpd) cannot be
normally stopped using signal 15 (TERM).
It is really worth to notice that using rails 1.1.0 the issue was not
present.

Thanks in advance for any solution,
Luca