Firewall API's

[williams @ va . arca . com (Jeff Williams)]

We're in the middle of a firewall selection effort and we need some help. 
We're wondering whether or not it is common practice to provide an API so
that we can create our own proxy applications if we want to.  At least one
vendor has said "No way".

Is it reasonable to expect such an API with a firewall product? What's the
best way to find out which ones do or do not?

Thanks in advance for any help,

--Jeff  <williams @
 arca .
 com>