I just want to make one general comment on this since there have been
some very good replies.
IMHO: There should be a dedicated firewall between any 24x7 connection,
whether cable modem, DSL, Satellite, or other. Even a simple NAT box
like the Linksys routers are much better than none. (But be careful of
the wireless so as not to allow others to use your connection).
But, as a good method of protection, turning on firewall software in
each node in the internal network provides an extra level of protection,
and can also indicate if the firewall is doing its job.
And, the final issue is properly configuring the firewall. A
Linksys-type of router is inexpensive and will serve many home networks
well because it does not require much configuration. A more
sophisticated firewall may lead to complacency and can be easily
misconfigured.
--
Jerry Feldman