Simple question

[dcostello @ cmol . com]

This may sound like a simple question and it probably is.  If I have a router
that is capable of IP address and UDP port filtering both inbound and outbound,
why would I need a firewall?  If I understand this correctly I could setup my
router to only allow incoming www traffic to my web server by setting a filter
that denies everything except UPD port 80 traffic to 10.1.1.1.  I'm just getting
into this area and have a few questions.

Thanks,
Dave Costello