iptables可以支持多少条规则？

最近有人问我，对此我无能为力。我知道这是一个开放式问题，但是您可以在表/链中安装的规则数量是否有限制？如果是这样，我如何找到它？我猜这会因机器而异。

引用来自 Jan Engelhardt

The theoretical upper limit of maximum number of rules for a 32-bit
environment would be somewhere around 38 million, but you could also
construct a rule that is so crowded with matches that even it won't
fit, so the lower limit of max rules is 0.

http://www.spinics.net/lists/netfilter/msg51895.html

根据linuxquestions.org的说法，在一台32位计算机上，IPTables将支持大约25,000条规则。除此之外，尤其是从27,000起，事情开始变得不稳定。