From mboxrd@z Thu Jan  1 00:00:00 1970
From: Yuan ChunYang <cyyuanml@sonata.iscas.ac.cn>
Subject: priority in netfilter
Date: 09 Jul 2003 11:40:10 +0800
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Cc: netfilter-devel <netfilter-devel@lists.netfilter.org>
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Can somebody explain priority in netfilter hooks?
We know netfilter defined 
 enum nf_ip_hook_priorities {
         NF_IP_PRI_FIRST = INT_MIN,
         NF_IP_PRI_CONNTRACK = -200,
          NF_IP_PRI_MANGLE = -150,
          NF_IP_PRI_NAT_DST = -100,
          NF_IP_PRI_FILTER = 0,
          NF_IP_PRI_NAT_SRC = 100,
          NF_IP_PRI_LAST = INT_MAX,
 };
They are ordered by ascend. But i do not know when to use which priority?