Micheal Patterson wrote:
.
----- 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
Confidentiality Notice: This e-mail message, including any attachments,
is for the sole use of the intended recipient(s) and may contain
confidential and privileged information. Any unauthorized review, use,
disclosure or distribution is prohibited. If you are not the intended
recipient, please contact the sender by reply e-mail and destroy all
copies of the original message
_______________________________________________
[EMAIL PROTECTED] mailing list
http://lists.freebsd.org/mailman/listinfo/freebsd-questions
To unsubscribe, send any mail to
"[EMAIL PROTECTED]"
Thanks for your help.
I was running nmap against my public or outside interface. This is my
first FreeBSD firewall, so I am sure my rules are not optimal, however,
the firewall appears to be doing what I want. I gathered these rules
from a number of how-to's and postings on the web with only a partial
understanding of what they actually do (yes, I know, problem # 1).
Here are the rules that I have that keep-state on the outside interface:
#For DNS
add 01300 pass udp from ${oip} to any 53 keep-state
# For NTP
add 01400 pass udp from ${oip} to any 123 keep-state
# For VPN
add 01500 pass gre from any to any keep-state
# For ICMP
add 01600 pass icmp from any to any via ${oip} keep-state
Do you think these are causing the problem?
Norm Vilmer
_______________________________________________
[EMAIL PROTECTED] mailing list
http://lists.freebsd.org/mailman/listinfo/freebsd-questions
To unsubscribe, send any mail to "[EMAIL PROTECTED]"
