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----- Original Message ----- From: "Norm Vilmer" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Thursday, September 16, 2004 11:57 PM
Subject: Too many dynamic rules, sorry
If I repeatedly nmap my FreeBSD 4.10 machine configured with ipfirewall,
I get the message "Too many dynamic rules, sorry". Doing a sysctl -a
|grep ip.fw I can see the the net.inet.ip.fw.dyn_count has reached the
max value of 8192 that I set. The net.inet.ip.fw.dyn_ack_lifetime is set
to 300, so the dynamic rule count starts going down after about 5
minutes after the simulated attack.
Questions:
When this happens, if my firewall still fully operational, in other words can I safely ignore this message?
Is there a way to fix this?
The error "Too many dynamic rules, sorry" will cause the system to drop any packets that are covered by a keep-state entry. So, the firewall, while operational, is in a dead lock down state for any outbound traffic until the dynamic rules clear out. I'm hoping that you're checking the system with nmap from behind it, because if your outside the firewall, then you're keeping state in inbound traffic and that's bad. You only want keep-state from traffic leaving that system, not to it.
--
Micheal Patterson TSG Network Administration 405-917-0600
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