Connection or process limit

Connection or process limit

[Pete Davis]

I am trying to find out the capacity of my iptables firewall.  Is there
a limit for the state table in terms of connections it can track?  How
about a Linux limit on processes, etc.?  We have a DS3 at 15mb/s and I
want to make sure my box can handle it before I continue on my project. 
Currently, I have a 500mhz Intel box with 256mb of memory and 
server-class Intel 10/100 NICs.  It seems this should be able to handle
it if I tweak the kernel configs properly.

This box is going to be acting more as a screening router than a
firewall (it is a bridging + iptables firewall... no IP on the box). 
The rule set will be minimal as I just want to screen out obvious bad
traffic from getting to the network OUTSIDE my firewall (from the
internet).  The main firewall does a great job for the internal stuff
but I want to help the external stuff as much as possible without
interfering with legitimate traffic. 

Any comments, helpful hints, words of experience...?