Optimizing ipfw?

[Tim Daneliuk]

On 11/23/19 11:46 AM, Michael Sierchio wrote:
> Don't use specific rules per CIDR block, use tables.  You can efficiently
> handle hundreds of thousands of CIDR blocks and IPv6 prefixes in a single
> table, or multiple tables.  You can assign the argument based on country
> code or some such. You can add and delete CIDR blocks, and even swap tables
> so you can do it atomically.

Aha!  Thanks.  So, I added this to my firewall startup code:

  ###
  # Block Naughty IP Addresses/Spaces
  ###

  # Use ipfw tables for efficiency

  for addr in `cat ${NAUGHTYFILE}`
  do
    ${FWCMD} table 10 add ${addr}
  done

  ${FWCMD} add deny all from table\(10\) to any via ${OIF}


ipfw show does show that new table being referenced and the table shows the IPs and CIDR blocks
I want stopped, but I have no affirmative proof this is working yet.

It does, however, no longer clobber network performance as you noted.  So ... thanks again!

P.S. Is there a way to get ipfw to dump everything it is blocking including the stuff in the table?