RE: em0, polling performance, P4 2.8ghz FSB 800mhz

From: Mike Silbersack (silby_at_silby.com)
Date: 02/29/04

  • Next message: Deepak Jain: "Re: em0, polling performance, P4 2.8ghz FSB 800mhz" 
    Date: Sun, 29 Feb 2004 00:13:21 -0600 (CST)
To: Don Bowman <don@sandvine.com>

    On Sat, 28 Feb 2004, Don Bowman wrote:

    > You could use ipfw to limit the damage of a syn flood, e.g.
    > a keep-state rule with a limit of ~2-5 per source IP, lower the
    > timeouts, increase the hash buckets in ipfw, etc. This would
    > use a mask on src-ip of all bits.
    > something like:
    > allow tcp from any to any setup limit src-addr 2
    >
    > this would only allow 2 concurrent TCP sessions per unique
    > source address. Depends on the syn flood you are expecting
    > to experience. You could also use dummynet to shape syn
    > traffic to a fixed level i suppose.

    Does that really help? If so, we need to optimize the syncache. :(

    Mike "Silby" Silbersack
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