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--- ipfw [2009/07/15 03:22] – created k2patel
+++ ipfw [2020/08/10 02:35] (current) – external edit 127.0.0.1
@@ Line 2: / Line 2: @@
 Simple but nice firewall.
+[[http://www.freebsd-howto.com/HOWTO/Ipfw-HOWTO | Good Reading]]
 ==== How to create forward for port ====
@@ Line 16: / Line 17: @@
 </code>
 NOTE : sysctl net.link.ether.bridge_ipfw=1   (this value enable the snort)
+==== Common Attack Prevention ====
+**# XMAS tree**
+<code bash>
+ipfw add 00011 deny log tcp from any to any in tcpflags fin,psh,urg recv em0
+</code>
+**# NULL scan (no flag set at all)**
+<code bash>
+ipfw add 00012 deny log tcp from any to any in tcpflags !fin,!syn,!rst,!psh,!ack,!urg recv em0
+</code>
+**# SYN flood (SYN,FIN)**
+<code bash>
+ipfw add 00013 deny log tcp from any to any in tcpflags syn,fin recv em0
+</code>
+**# Stealth FIN scan (FIN,RST)**
+<code bash>
+ipfw add 00014 deny log tcp from any to any in tcpflags fin,rst recv em0
+</code>
+**# forced packet routing**
+<code bash>
+ipfw add 00015 deny log ip from any to any in ipoptions ssrr,lsrr,rr,ts recv em0
+</code>
+**# ACK scan (ACK,RST)**
+<code bash>
+ipfw add 00016 deny log tcp from any to any in tcpflags ack,rst recv em0
+</code>
+**#deny fragments as bogus packets**
+<code bash>
+ipfw add 00017 deny log all from any to any frag in via em0
+</code>